misfiring SES light

[98gpking]

heres the deal. i change my plugs and wires. after i do this my RPM's become kinda jumpy. and the car randomly bogs out a little. well i open my hood to find one of the vacuum lines off not sure what the parts called it goes to. so i reconnect, i also messed around with a few wires to make sure all connections were tight and restart my car. it runs for about 2 minutes and now my SES light comes on.

i dont know if its coincidence or if that vacuum line shouldn't be on haha.

anyways im almost 100% sure the SES light is for a misfire because i can hear it in my exhaust. but the plugs and wires are brand new. the only thing i can think of is i didnt gap the new plugs because autozone said the Autolite 104 plugs dont require gapping and i didnt have the tool to check.

could gapping be causing this problem...if so why did it take almost 40 miles for the SES light to come on???

[GTP Dad]

Have the code pulled and if it is a random misfire then I would remove the plugs and gap them. Never believe what they say at an auto parts store especially when it comes to your car. They will tell you anything to get you to purchase the parts. Regap the plugs and the issue should go away. Just make sure you get all the wires fully engaged on the plugs as well.

[hercman]

You need to gap the plugs.

Most places Autozone for one will pull the code for you. Or you can buy yourself a cheap code reader this way you can pull when ever you want and even erase the code (turn the SES light off) so you can see if you indeed did fix it.

[BNaylor]

Originally Posted by GTP Dad

Have the code pulled and if it is a random misfire then I would remove the plugs and gap them. Never believe what they say at an auto parts store especially when it comes to your car. They will tell you anything to get you to purchase the parts. Regap the plugs and the issue should go away. Just make sure you get all the wires fully engaged on the plugs as well.

Just for insight and history Lynn the OP had a recent prior relevant thread right before addressing this issue.

I recall he is using the Autolite AP/APP single or double Platinums and not the typical copper core like most of us use and whereby you can readily regap depending on the mod especially SC pulley size and whether the plug manufactuer recommends for or against it. I vaguely remember the Autolite AP/APP come .060" which is the stock gap. On most double platinum brands including AC Delco and Laser Iridium it is highly recommended not to regap the plugs as you may cause damage to the spoon on the electrode. AL copper core no problems regapping or checking gap to make sure it is right. We have an old thread going way back with recommended gaps on the AL copper cores someplace. No one has mentioned what to gap it to based on the OP's circumstances.

http://www.automotiveforums.com/vbul...d.php?t=884412

[eippermx]

Bob,

Just a "for what its worth." I just installed APP 606's in my '99 Flaming Tomato 's newly transplanted engine last Saturday. I learned years ago not to trust factory gapping. In my case, when I checked the gap on the new APP 606's two of them were gapped .60, the other 4 were gapped either .62 or .63.

mark

[BNaylor]

Originally Posted by eippermx

Bob,

Just a "for what its worth." I just installed APP 606's in my '99 Flaming Tomato 's newly transplanted engine last Saturday. I learned years ago not to trust factory gapping. In my case, when I checked the gap on the new APP 606's two of them were gapped .60, the other 4 were gapped either .62 or .63.

mark

It is always a good idea to verify or check the gap on new or old spark plugs. But from what I see on your annecdotal info that is pretty good considering you had 4 that were just 2-3 hundreths of an inch off. Do you really think the gap being off that minor amount would cause a misfire condition like the OP has?

I used the Autolite AP605 Platinums in my Regal GS when the cost of gas was too high for about a year so I could periodically run mid-grade gas. Keep KR in check. Here is one from cylinder #3. With the feeler gauge shown (.060) in the pic the gap looks right on to me. Too bad I can't find the other 5 but what I do remember from my old memory is all gaps were good with no adjustment required before installation. I replaced them with the NGK TR55IX Iridiums and incidently those gaps were right on at .060". Man, I must be one lucky dude.

[GTP Dad]

Bob,

I understand that gapping of some plugs is not necessary but I have never trusted the factory gapping and always check them. My son changed the plugs for me in the GTP when we had it apart and he didn't check the gap. Put in Autolites. Had raging multiple misfires. Pulled the plugs and the gaps were way off. Regapped and the misfires went away. I guess I do this out of habit.

[BNaylor]

Originally Posted by GTP Dad

Bob,

I understand that gapping of some plugs is not necessary but I have never trusted the factory gapping and always check them. My son changed the plugs for me in the GTP when we had it apart and he didn't check the gap. Put in Autolites. Had raging multiple misfires. Pulled the plugs and the gaps were way off. Regapped and the misfires went away. I guess I do this out of habit.

Lynn, I don't disagree with your experiences and every one or situation will be unique. What specific Autolites was that on? Copper core, single platinum (AP) or double platinum (APP)? As I mentioned earlier always a good idea to check plug gap on any brand spark plug replacement just to be sure. But I've probably installed more Autolite spark plugs of varying types than anyone on this forum and I very seldom if ever had to adjust them nor were they ever way off from the stock gap of .060". <---Particularly referencing the AP and APP not the copper core.

Now back to the issue at hand and what the OP should gap them to depends on what mods are there especially with a smaller 3.4" SC pulley. I recall when I ran the 3.4" pulley that we close the gap (make smaller) to around .055-.058 and do not use the stock gap of .060" which is now really moot for the OP.

Also, it depends on the plug heat range.

Here is a general guide to follow on Autolite spark plugs for any L67 SII 3800 engine (supercharged):

Non-intercooled:
Less than 3.8” factory to 3.5": Autolite 605 @ .055-.057” gap (or AP605/APP605 platinums @.060”)
3.4-3.25” pulley: Autolite 104 @ .052-.054” gap
3.1-3.0” pulley: Autolite 103 @ .047-.050” gap
2.9-2.7” pulley: Autolite AR94 (4 range colder race plug) @ .044-.046”

Note : Stock is 606 with 3.8" SC pulley.

[98gpking]

Originally Posted by BNaylor

Lynn, I don't disagree with your experiences and every one or situation will be unique. What specific Autolites was that on? Copper core, single platinum (AP) or double platinum (APP)? As I mentioned earlier always a good idea to check plug gap on any brand spark plug replacement just to be sure. But I've probably installed more Autolite spark plugs of varying types than anyone on this forum and I very seldom if ever had to adjust them nor were they ever way off from the stock gap of .060". <---Particularly referencing the AP and APP not the copper core.

Now back to the issue at hand and what the OP should gap them to depends on what mods are there especially with a smaller 3.4" SC pulley. I recall when I ran the 3.4" pulley that we close the gap (make smaller) to around .055-.058 and do not use the stock gap of .060" which is now really moot for the OP.

Also, it depends on the plug heat range.

Here is a general guide to follow on Autolite spark plugs for any L67 SII 3800 engine (supercharged):

well i took out all my plugs and re-gapped them to about .055-.057. well see how it runs. 4/6 plugs were pregapped at .043 and the other 2 were at .038 so they were waaay to close.

providing it runs better now i will throw on the 3.4 pulley

[BNaylor]

Just to clarify for our audience and reiterate what specific Autolite spark plugs are you using? ....heat range and specific type. Post a pic if you can.

Technically you should use the standard copper core and not the platinums.

[98gpking]

Originally Posted by BNaylor

Just to clarify for our audience and reiterate what specific Autolite spark plugs are you using? ....heat range and specific type. Post a pic if you can.

Technically you should use the standard copper core and not the platinums.

using Autolite 104 platinum plugs.

[BNaylor]

Originally Posted by 98gpking

using Autolite 104 platinum plugs.

Thats what I thought. Then you are using the wrong spark plugs. Where you get your initial information or advice to use the colder range Autolite Platinums? The Autolite spark plugs referred on this and other GP forums are the copper core not the platinums. All advice related to mods such as supercharger is centered around using those only. For example I use the 103 not the AP103 or APP103 due to running a 3.0" SC pulley. The different type of Autolite plugs (i.e. - copper core, platinum, double platinum, xtreme performance) do not work the same and conduct differently due to material composition.

[98gpking]

Originally Posted by BNaylor

Thats what I thought. Then you are using the wrong spark plugs. Where you get your initial information or advice to use the colder range Autolite Platinums? The Autolite spark plugs referred on this and other GP forums are the copper core not the platinums. All advice related to mods such as supercharger is centered around using those only. For example I use the 103 not the AP103 or APP103 due to running a 3.0" SC pulley. The different type of Autolite plugs (i.e. - copper core, platinum, double platinum, xtreme performance) do not work the same and conduct differently due to material composition.

not to sound like a jerk because i appreciate all your help ive posted many times on here and you of all people have helper me ALOT over the past couple years. but this is my 3rd set of plug wires everyone seems to tell me differently on anything i buy. ive gone through 3 sets of wires, 2 different trans fluids, different air/fuel filters. personaly i dont really give a crap about this car anymore im just sick of dumping money into the gas tank. its only aggervating becuase I KNOW that i should be getting more then 210 miles to a tank highway cruisin at a steady 60mph. i got a new job that pays amazing. im selling this hunk of crap. buying a WS-6 like i had, and buying a 3000 GT for my daily driver. maybe ill have some differnt luck...who knows

[BNaylor]

Originally Posted by 98gpking

not to sound like a jerk because i appreciate all your help ive posted many times on here and you of all people have helper me ALOT over the past couple years. but this is my 3rd set of plug wires everyone seems to tell me differently on anything i buy. ive gone through 3 sets of wires, 2 different trans fluids, different air/fuel filters. personaly i dont really give a crap about this car anymore im just sick of dumping money into the gas tank. its only aggervating becuase I KNOW that i should be getting more then 210 miles to a tank highway cruisin at a steady 60mph. i got a new job that pays amazing. im selling this hunk of crap. buying a WS-6 like i had, and buying a 3000 GT for my daily driver. maybe ill have some differnt luck...who knows

Not to sound like jerk in return you're welcome to do what you want with your Grand Prix and money but I seriously doubt you received any intentional misinformation or disinformation on this forum. Based on your three total recent posts and the muddled replies from various members that is why I decided to work with you to help get your issue straight or in the right direction. In reality I have better things to do than wasting my time and knowledge. To start against anyone's recommendation you used Bosch spark plugs when we told you not to. I am well aware of your prior post history and participation on this forum. Then you inadvertently assume the Autolite spark plugs that we all were referring to are the Platinums (AP) and then go out and get them before seeking any advice. In one of your prior posts you failed to mention anything about going to a 3.4" SC pulley which is worst thing to do if you are experiencing fuel economy problems and if that is your primary concern. Most of us get good results to include performance and gas mileage out of our Grand Prixs to include modded ones so you sound like the exception not the rule as far as the problems you are having. You didn't have much luck with your '98 either.

If you think your problems or bad luck will go away with another WS6 or Mitsu then I've got news for you. The grass is never greener on the other side of the hill.

End of lecture.

[jessiebighamKC]

Ok Im lost! Did u ever fix the random misfire or not? I still havent fixed mine but there was a few things a replaced that was causing it to have a random misfire. Heres the list of things Ive replaced to try n eliminate the problem. Autolite 104's that I re-gapped, new spark plug wires, ignition control module, ignition coil packs, idle air control valve, throttle position sensor, PCV Valve, Valvoline High Mileage Engine oil, K&N Oil Filter, K&N Air filter, Mass Air Flow Sensor, Ambient Air Sensor and changed Tranny Fluid and Filter. I know some of the things didnt have to do with it but just listed the things Ive replaced and still havent fixed the random misfire. Only thing left to replace that I can think of is the PCM. Which I can get for $50 but just waiting on the exact year of the car I got to come in. Also this is on a 2001 GTP.