Intake PoppIng

Yeah what the deal with my intake makeing a poppin sound at High Rpm< it seems to only do it when i floor it in 1st gear< And when it pops it lose power, It only does it at about 5000 to 6000 RPM in 1st gear> i cleaned the MAF and it still does it< What Happens when the IAT sensor goes bad> Could this be the Problem< Its nothing show up on the OBDII scanner so the engine light isnt on< it drives good for everyday driving but if i wanted to race somebody< they would pretty much hand it to me right now> So can anybody help :banghead:

The pop you hear is the engine hitting the rev limiter. It kills the igniton so that you can't damage the engine and when the rpm drops below the preset limit it runs well. Stay below the limiter and the popping should go away.

i know what the rev limiter is< That happens when the car is in Park, But i'm talkin about while i'm driving and i just suddenly floor it and when it get hit in rpm it pops and boggs out< i have new sparks plug and i really havent checked the fuel filter but this problem doesnt effect everyday drving so i dont think the Fuel F is the problem<

try changing your blinker fluid.HAHHA jk maybe its the gas i know on gtp if u put in cheap gas too long the supercharger knocks kinda loud.? try that

yeah i have a gt but i put 93 in there b/cuz i have a DHP PCM so i started that already< I clean the MAF but i didnt take it out, i think i'm going to try to take it out and clean it again as some as i get the tools to do it

The rev limiter works at other times not just while in park. If you exceed the preset limit which is in the 5-6K range it will do the exact same thing as it does in park it will cause it to pop like you say it is doing.

The rev limiter works at other times not just while in park. If you exceed the preset limit which is in the 5-6K range it will do the exact same thing as it does in park it will cause it to pop like you say it is doing.

I agree with Lynn. It could be the rev/rpm limiter kicking in.

The rev or rpm limiter is made to kick in shortly after the maximum shift point which is 5800 rpms for a stock PCM or DHP PCM without Performance Shift mode.

In a DHP PCM, if Performance Shift is working and active then the maximum shift point is 6000 rpms.

In my experiences the tranny in full automatic mode (drive) will shift before the rev limiter sets in unless you are manually shifting which could cause the limiter to go active.

I agree with Lynn. It could be the rev/rpm limiter kicking in.

The rev or rpm limiter is made to kick in shortly after the maximum shift point which is 5800 rpms for a stock PCM or DHP PCM without Performance Shift mode.

In a DHP PCM, if Performance Shift is working and active then the maximum shift point is 6000 rpms.

In my experiences the tranny in full automatic mode (drive) will shift before the rev limiter sets in unless you are manually shifting which could cause the limiter to go active.


Well I have DHP PCM and P-Shift and i usually keep it off< But this Popping sound start at about 5000 RMP and pops and boggs intil its time for the car to Shift at about 5800 and is seems to only do it in 1st gear well as far as i can tell<I dont manually shift it at all> Could it be the IAT snesor< what happens when they go bad ( i thinking about replacing everything on the car it a 02 with 125000 miles it and i think it time for everything to be changed) What that Part Number or a IAT sensor

Well I have DHP PCM and P-Shift and i usually keep it off< But this Popping sound start at about 5000 RMP and pops and boggs intil its time for the car to Shift at about 5800 and is seems to only do it in 1st gear well as far as i can tell<I dont manually shift it at all> Could it be the IAT snesor< what happens when they go bad ( i thinking about replacing everything on the car it a 02 with 125000 miles it and i think it time for everything to be changed) What that Part Number or a IAT sensor

If you are getting a cutout or misfire way before 5800 - 6000 rpms at 5000 rpms then it sounds like you do have a problem.

The IAT doesn't cost much to change out. It can be ohmed out with a multimeter to see if it is within calibration just to be sure.

It sounds more like a MAF sensor or plugs/wires to me. What brand ignition wires or spark plugs. What is the plug heat range or number?

If you are getting a cutout or misfire way before 5800 - 6000 rpms at 5000 rpms then it sounds like you do have a problem.

The IAT doesn't cost much to change out. It can be ohmed out with a multimeter to see if it is within calibration just to be sure.

It sounds more like a MAF sensor or plugs/wires to me. What brand ignition wires or spark plugs. What is the plug heat range or number?

Well this Problem doesnt happen intil i floor it< so can it still be plugs> And i have the DHP so i put 93 gas in there MOST of the time< so could it be Reg Gas mess it up> And Does Auto Zone Sell IAT sensors and where can i get a Multimeter< and cant you put a resistor in there 4.7 ohms>

Well this Problem doesnt happen intil i floor it< so can it still be plugs> And i have the DHP so i put 93 gas in there MOST of the time< so could it be Reg Gas mess it up> And Does Auto Zone Sell IAT sensors and where can i get a Multimeter< and cant you put a resistor in there 4.7 ohms>

The spark plugs are always a possibility. When flaky they misfire at higher rpms like in a range of 4000 - 5800 rpms. All it takes is one bad one.

AZ should have the IAT - Wells Part Number SU176 $9.99. Cheaper than trying to get a multimeter. The resistor trick normally does not work.

The MAF sensor is still a possibility. Also, do you have the throttle body screen in or out?

I got in and and top it out on the freeway just to see what it would do well i didnt top it out but i was just tryin to make it throw me a engine code and it did PO300 random/Multiple cylinder misfire dectected> I just read on another forum(camaro) and they replied to another dude it may be the ignition> Now i know i have a bad ignition switch and was going to fix that as some as the Part get here i order from GMPARTDIRECt< do anyone know how long it take i order it today> But anyway Could this be the problem in a Grand PRix< And it does it only at like 5000 to 5400 and it runs like it should after that intil it shift so from 5400 to about 5800 its back to normal.

Where can i find a list or Part number< Would anyone say i need a new coil pack< i know that part is probaly expensive huh

Where can i find a list or Part number< Would anyone say i need a new coil pack< i know that part is probaly expensive huh

The coil packs and ignition control module (ICM) are a possbility. Coil packs run around $40. You can swap the coil packs around for troubleshooting purposes to determine of you really neeed one. The ICM can be tested at places like Autozone.

problem solved, fuel filter< well i'm nothing going to say it sloved but it was clogged but i havent gotten to test it at high speeds today.

Well i was wrong< its still misfire-ing>any other suggest, Coilpack maybe, I dont know but could this be just a fuel deliverey problem it only misfire at high rpm.

How do you check to see if your coil pack are bad< i ran the engine and pull my 6 wire off the pack and it shock the Sh*2 out of me< is there a easier way< what to do > i know my number 6 is good enough< but it sayin Multiple misfire< so do you'll think it a gas issue> I put some injection cleaner and still nothin yet but i guess i will just wait intil it kick in< Full tank or 93 gas and Lucas injector cleaner

How old are the plugs and wires and what brand are they (you never answered Bnaylor's question so I figured I'd repeat it)? Most high RPM misses are ignition related. If you installed Bosch Plugs (JUNK) or generic branded wires, that is most likely your issue (stick with AC-Delco or Autolite plugs and AC Delco or Taylor [great performance brand and the price won't break you] wires). It is highly unlikely that all your coil packs went bad at once. If only one coil pack was bad, it would only show a misfire code for the two cylinders that coil fires.

Well i took my 6 plug wire off and it shock the mess out of me < and then i just took one off one by one and listen from the popping sound from the coil< sparking> so all my coils are fireing< but i was going to get news one with plugs and wire when i get paid< i was going to get those MSD coil off of 3800performance with the autolite plugs<well i do everything to my car< but i dont think i can change the plugs< i know how but GM has made it pretty tuff to change them so i guess i will just take it to them< anybody have a Ballpark estimate on changing plugs from the dealership> And i really dont know what kind of plugs in there My Uncle change them when my MAF went out about a 60000 miles ago < so is the igntion control mod< the coil packs of something totally different.

Well i took my 6 plug wire off and it shock the mess out of me < and then i just took one off one by one and listen from the popping sound from the coil< sparking> so all my coils are fireing< but i was going to get news one with plugs and wire when i get paid< i was going to get those MSD coil off of 3800performance with the autolite plugs<well i do everything to my car< but i dont think i can change the plugs< i know how but GM has made it pretty tuff to change them so i guess i will just take it to them< anybody have a Ballpark estimate on changing plugs from the dealership> And i really dont know what kind of plugs in there My Uncle change them when my MAF went out about a 60000 miles ago < so is the igntion control mod< the coil packs of something totally different.
60,000 miles on cheap plugs/wires could be the cause of your problem. And when you need to check the coils, unpluging the wires at the coil, not only gives you a good zap. But can also start "carbon tracks" on the surface and inside of your coils.(bad thing)

If you pull the bolt on the "dogbone" engine mounts, you can swing the whole motor forward and get the the rear bank a little easier.

Oh and in my opinion stock coils are = to if not better than the MSD's, just my :2cents:

If you pull the bolt on the "dogbone" engine mounts, you can swing the whole motor forward and get the the rear bank a little easier.

Removing the engine mounts and tilting the engine to get to the rear bank of plugs is totally unneccessary. I've never had to do that on any of the 3 GM "W" body with SII 3800 I own. All it takes is the right tools and patience.

Removing the engine mounts and tilting the engine to get to the rear bank of plugs is totally unneccessary. I've never had to do that on any of the 3 GM "W" body with SII 3800 I own. All it takes is the right tools and patience.
I'm going to try to do my plugs so I'm wondering what are the right tools?

I'm going to try to do my plugs so I'm wondering what are the right tools?

Don't tell me you have the original spark plugs with over 300K miles. :lol:

The front bank is a no brainer but for rear, I use a special 3/8" ratchet with an articulating head. Commonly known as a spark plug ratchet. Also a short extension (3") and a spark plug 5/8" socket with built in universal joint. Also to get to #2 and #4, it helps to remove the bracket that holds the front 02 sensor wiring harness and where you slip in the rear part of the plastic engine cover. Just two 13mm nuts holding it onto the exhaust manifold. For #6 the 02 sensor is in the way but you can work around it or simply remove the 02 sensor and reinstall upon completion. AZ has the special 02 sensor socket for around $9.00. Plus while 02 sensor is out it doesn't hurt to inspect and service it by cleaning with carb cleaner.

The biggest problem you will have is getting the old spark plug boots off so it will be a good idea to have new AC Delco Premium Silicone 7mm wires ready to go. Also, stay with the OEM AC Delco spark plugs. Coat the ceramic of the new plugs with dielectric silicone grease so the next plug service will be easier. Good luck and have fun!

Don't tell me you have the original spark plugs with over 300K miles. :lol:

The front bank is a no brainer but for rear, I use a special 3/8" ratchet with an articulating head. Commonly known as a spark plug ratchet. Also a short extension (3") and a spark plug 5/8" socket with built in universal joint. Also to get to #2 and #4, it helps to remove the bracket that holds the front 02 sensor wiring harness and where you slip in the rear part of the plastic engine cover. Just two 13mm nuts holding it onto the exhaust manifold. For #6 the 02 sensor is in the way but you can work around it or simply remove the 02 sensor and reinstall upon completion. AZ has the special 02 sensor socket for around $9.00. Plus while 02 sensor is out it doesn't hurt to inspect and service it by cleaning with carb cleaner.

The biggest problem you will have is getting the old spark plug boots off so it will be a good idea to have new AC Delco Premium Silicone 7mm wires ready to go. Also, stay with the OEM AC Delco spark plugs. Coat the ceramic of the new plugs with dielectric silicone grease so the next plug service will be easier. Good luck and have fun!

No I don't have the original plugs in there. There were changed in Oct of '99 at 126,000 miles. Don't tell me AC Rapidfires aren't good plugs. I hesitate to fool with taking them out. They are probably welded in by now. Not sure what an articulating ratchet is. I've been thinking about getting one of those new ratchets that you can twist the handle either way and it rotates the socket.

No I don't have the original plugs in there. There were changed in Oct of '99 at 126,000 miles. Don't tell me AC Rapidfires aren't good plugs. I hesitate to fool with taking them out. They are probably welded in by now. Not sure what an articulating ratchet is. I've been thinking about getting one of those new ratchets that you can twist the handle either way and it rotates the socket.

There are a lot good, innovative tools available to make the job easier. All I ever use are in the pic below. One standard 5/8" spark plug socket, one with universal, 3" extension, spark plug rachet where the head moves to different angles. Plus it has a special bend and it is longer that the standard 3/8" ratchet. BTW - Nothing wrong with Rapidfire Platinums since they are AC Delco.

http://i5.photobucket.com/albums/y186/lizzywiz/sptools.jpg

HAHA!
I hav been working on a few GPs over the last weeks.
Done the plugs on one yestarday..

The Manuals stated to tilt the engine forward, :screwy:
Didnt hav all Day!

I used the 5/8 socket, 3" extension, short swivle(which I didnt really need), and a ratchet.
It took longer to get #6 (3.8) then all the rest combined :grinyes:

Had to get this one from the drivers side , though I droped the plug in the hole :banghead:, and it took forever to get it out, next time I'll remember the "magnet" :)

The back plugs in this GP had Never been changed either, pretty tight too.
Also some Anti-seize on those plugs threads works great for the next removal :thumbsup:








Now I remember why I hav only had 1 Grand Prix, and it was a 71' :lol:

I use a "wobble" extension and a flex head ratchet similar to what Bob pictured on mine. The wobble gives you just enough flex to clear the oxygen sensor without too much making it hard to deal with. IMO, most socket u-loints get loose as they get old, and flop around to much. You shouldn't have to pull the engine forward.

bluegt02 said it would be easier, not that it HAD to be done, and he is right is easier to remove the dogbone in front and it only takes a couple min. and w/ as little room there is back there every little bit matters......just ask your knuckles.lol

If you pull the bolt on the "dogbone" engine mounts, you can swing the whole motor forward and get the the rear bank a little easier.

bluegt02 said it would be easier, not that it HAD to be done, and he is right is easier to remove the dogbone in front and it only takes a couple min. and w/ as little room there is back there every little bit matters......just ask your knuckles.lol

It is not any easier and will add 20 - 30 minutes or more to the job. Upon reviewing his statement he left out a lot of steps. His statement quoted above implies that you have to remove the mounts which you can see by others weighing in to include me that is not the case. Most 3800 SII engines will not just miraculously drop or move forward after removing both wishbone engine mounts to give you any significant clearance. And getting everything back together specifically moving the engine back into position and lining up the mounts is a hassle and makes a simple job more tedious.

Most hand, i.e. knuckle damage will come from trying to get the spark plug ignition wire boots off or operating the ratchet and not due to the limited engine to firewall clearance which IMO is sufficient.

YA Bobs right,
you loosen those mounts, and the motor tilts back :nono:
And I did hav another secret Tool, the 1.5" extension :)

And it does add 20mins or so to the job when you remove the motor M.

What the Gap size supposed to be on the spark plugs?

What the Gap size supposed to be on the spark plugs?

Gap = .060.

What brand spark plugs do you have to include heat range or just provide the number off it.

Be careful re-gapping platinum plugs. Hamfisted attempts can result in dislodging the platinum disc causing more problems than a couple thousandths gap variance. If you bought new plugs and the gaps are monkeyed up, take them back and get some that aren't.

Ya, about 99% of plugs are pre gapped,
but you do run into some that are off a little bit.

also to add to the popping topic....
My GA GT does that popin when the rpms are maxed, though mine sounds like its coming from the bottom of the engine... :dunno:
I just dont max it out, it doesnt do it :)

sorry to cause so much strife, i needed to do this on my 94' grand prix to get around the alternator and get that plug under it. I havent done this job on my 3.8 yet, i assumed it was just like my 3.1. My apoligies

I have the Autolite 606< are those good> i took richtazz advice to not to get bosch/ if he wouldnt have told me those would have been the one i would have got< but are autolite good< i see those and UKG plugs on all the Grand Prix website so i just got those

I have the Autolite 606< are those good> i took richtazz advice to not to get bosch/ if he wouldnt have told me those would have been the one i would have got< but are autolite good< i see those and UKG plugs on all the Grand Prix website so i just got those

You should have gotten either AC Delco Iridium 41-101 or Platinum 41-921 which work the best.

The Autolites are good plugs and should work fine. It sounds like the copper core so the only difference is they will not last as long as the Iridiums or Platinums.

The 606 is the direct replacement for a stock spark plug and is the same heat range. Autolite Platinums are AP606. The gaps on Autolites are set for .060 so you will not have to worry about that.

So do you think spark plugs will fix the problem with multiple misfire/ It starting to do it at low rpm now around 3000/ so the problem has gotten wrost basically. It still throwing the PO300 OBDII code. So if this doesnt work what should i try next I got new Fuel Filter, New Spark Plugs and wire tomarrow, coil seem to work fine and the car doesnt miss at Idle just driving it does it i cant go over 5000 rpm it doesnt have the power to b/cuz of the misfire. but i guess i will see 2marrow to see if it the plugs<wish me luck i going to try to do it myself.

So do you think spark plugs will fix the problem with multiple misfire/ It starting to do it at low rpm now around 3000/ so the problem has gotten wrost basically. It still throwing the PO300 OBDII code. So if this doesnt work what should i try next I got new Fuel Filter, New Spark Plugs and wire tomarrow, coil seem to work fine and the car doesnt miss at Idle just driving it does it i cant go over 5000 rpm it doesnt have the power to b/cuz of the misfire. but i guess i will see 2marrow to see if it the plugs<wish me luck i going to try to do it myself.

Hopefully but no guarantee. For misfires spark plugs are the best starting point. Try that and see what happens. Depending on your year model and in a worse case you could have a clogged CAT convertor if all else fails. Good luck!

I dont have a Cat< i got that cut off along time ago< Can the 1st os sensor cause a Misfire< B/cuz i change my plugs and i smelt a heavy smell of gas< i never smelt gas while changing plugs< could fuel richest cause misfire< b/cuz i have new plugs and wire and it still does it at high rpm and i know a guy with one of those TECH 2 scanner i think thats the name of it < its the scanner GM use and he said the my 1st O2 sensor voltage goes form 700 and drops to 0 and goes to 700 again back and from like a shortage or something while the car runs

No CAT? When did you do that. I know in Texas it is not a green state but we do have annual emissions testing at least in my county. Are you running a rear 02 simulator? Or is the PCM modded to run without one?

It sounds like you are getting a rich fuel trim problem which may or may not be related to the 02 sensor. If you smell fuel at idle I would check into the front 02 sensor. The PCM operates in two modes open and closed loop. The 02 sensor is used to help control the fuel injecting system for the ideal 14.7:1 air/fuel ratio and to control emissions, mainly after engine properly warms up in idle or while cruising (closed loop). However, when accelerating or WOT the 02 sensor is inhibited and out of the picture. This is open loop mode. Fuel injection control comes from other engine parameters like TPS position and MAF, etc in open loop mode.

If a Tech II machine confirms the 02 sensor is flaky then it would be a good idea to get it replaced. It could be affecting open loop mode due to not operating properly causing the rich trim via the PCM module especially if it has a short. BTW - Use an AC Delco 02 sensor only. Do not use a Bosch.

I live in texas but i from arkansas I still have AR tags and in arkansas we have no emissions test or inpections meanin i only pay 25 dollars year each for tags and everything opposed to payin 30 from inspection or how ever much for registration/ but it is illegal running no cat...>>


I just ordered a rear o2 simulator form 3800perfomance and it should be here any day now. So for the last year i've been riding with the engine light on PO420 for my rear 02 and the OBDII doesnt pick up failure from the 1st or aleast not yet, but when i 1st got my OBD it picked it up about 3yrs ago but the engine light wasnt on , i dont remeber the Code but it said (bank 1) sensor running rich of something like that. < The engine light never came on but it let me erase the code and it never came back< but the Tech II read the up and down voltage of it/ So could it be that when i cut my Cat off it cancal the 1st code or cover the 1st 02 sensor failure up

So you say there is a specail tool to take out O2 sensors< do you have a pic of one or thoses/ So if closed loop can it make the car misfire at high RPM or WOT. It seem like the problem get worst as the car warms up and also over time< it bearly dont anything when i lst posted this< now i cahnge Fuel filter it help alittle/ fuel injector cleaner really didnt do anything>>>> but then it starting misfiring while driving normal<<<>>> now i changed plugs and wires now it just do it at high RPM so is it possaible that my plugs when bad over time due to fuel richness< so if i dont fix the problem i could just mess the new plugs up can It

Where the Vac line, i hear on other site that may or can cause misfire

Problem Sloved, it was the Ignition Control Module. Thanks everybody

Glad to see you got it fixed, and you're welcome.