I have a 97 blazer with a 4.3 vortec engine..

Today I was driving up a hill on the highway, going about 70mph with the RPM's around 2000. All of a sudden, I lost power and the engine began to rev high -- upto around or past 3000 RPM's and I almost totally lost power. I lost power so much so that I barely made it up this long gradual hill.
When i lost the power and the engine reved, The service engine soon light began to flash and then eventually went on permanatly.
It is almost as though my truck won't go when it is at 3000 RPM's..

Does anyone know what this could be? Somebody help me!

BTW... The only other time the engine light has come on was when it hit 95mph and 3000 RPM's a couple of weeks ago.

Thanks!

-Christine

Get the codes scanned at autozone.

oh i am, my boyfriend works @ Advance Auto Parts and he brought the code computer home with him, now we just have to wait until he gets ti work this a.m. to print out the report and see what is wrong with it. It says it found 1 or more codes so we'll see...

Good, please keep us posted.

Check transmission fluid?

well.. the code that came up was P0300 which is an engine cylander misfire code. The guy @ the dealership said it could be stupid things like a messed up plug, wire, or just water in the gas, OR it could be an ignition coil or a fuel injector. Well its running okay now i guess, my boyfriend drove around with it. Now i just need to figure out, some how, what the hell is wrong with it! The plugs and wires all appeared to be fine. I put dry gas in lastweek so I dont know?
Any other suggestions??
Could it have been a transmission problem? Because I had my tranny rebuilt and it has broken 4 times since and has been rebuilt 4 more times, Im about to bring the guy to court over him not being able to fix my truck, and if this could be a transmission problem even better, but would an engine light go on if the tranny slipped?

Any suggestions... THANKS! and i'll keep u posted

Anyone else possibly think that it could be the 1997 faulty ignition switch?

Hmmm worth a shot no ?

Yip, transmission problem, weird codes, sounds like the 1997 ignition switch curse has struck again.

Yup the ignition switch went out on you right in the middle of the river, haha. How fast does it oull away from the curb? Slow and you have to start in low and shift it manualy? Mine on the highway warunning around 3,000 rpm too a new ignition switch solved it. $123 at the dealer a bugger to put in and a lot cheaper than a transmission.

Yup the ignition switch went out on you right in the middle of the river, haha. How fast does it oull away from the curb? Slow and you have to start in low and shift it manualy? Mine on the highway warunning around 3,000 rpm too a new ignition switch solved it. $123 at the dealer a bugger to put in and a lot cheaper than a transmission.

I have a 98 Chev. Blazer that I bought for my son. I have experienced the same damn S.E.S. code P0300 random cyl. misfire. The fuel pump was replaced by the auto dealer the day after we bought it, I have had my ace mechanic Dempsey change the plugs, AC Delco, wires, rotor, cap, and still get the SES light and code P0300, plus it runs rough. All of this was done in the past few weeks. My ignition switch is difficult to turn on. Did replacing your ignitiion switch cure your random misfire, and the P0300. Please advise a.s. a. p. this is bugging the heck out of me.
you can email me at mcfreil@cox.net. thanks,

I have a 98 Chev. Blazer that I bought for my son. I have experienced the same damn S.E.S. code P0300 random cyl. misfire. The fuel pump was replaced by the auto dealer the day after we bought it, I have had my ace mechanic Dempsey change the plugs, AC Delco, wires, rotor, cap, and still get the SES light and code P0300, plus it runs rough. All of this was done in the past few weeks. My ignition switch is difficult to turn on. Did replacing your ignitiion switch cure your random misfire, and the P0300. Please advise a.s. a. p. this is bugging the heck out of me.
you can email me at mcfreil@cox.net. thanks,
the 97's are knowen to have "faulty" igniton switches, the 98's are not, but that is not saying that its not a possibility that it has gone bad

Yup the ignition switch went out on you right in the middle of the river, haha. How fast does it oull away from the curb? Slow and you have to start in low and shift it manualy? Mine on the highway warunning around 3,000 rpm too a new ignition switch solved it. $123 at the dealer a bugger to put in and a lot cheaper than a transmission.
Yep I would try the ignition switch. the guy's on tis forum told me too I did and all my tranny problems went away for good. A good indication on mine was the engine light would come on and some times go off but always came back on again. and it felt like I was starting off in third gear. key would not come out of ignition.

Hey guys!! Well I've had my blazer for about 2 years... Anyway.. A few months ago my blazer got alittle "check engine light" happy and its been a neverending problem.

The details:

1997 chevrolet blazer ls 4x4 obviously wit the 4.3vortec.

Anyway.. When I drive it.. Shes usually fine.. BUT the last FOUR times I have driven up this one hill (its a long hill) around the middle of the hill the check engine light comes on and it starts chugging or like deiseling and I lose vacuum pressure to my brakes and have NO BRAKES! Anyway, when the engine light stops flashing it starts running alright again and i regain vacuum pressure to my brakes. Everytime I run a code check on the engine light it comes back as a cyl misfire.... Sometimes 6.. Sometimes 3&6.. I changed the plug, the coil back and im out of ideas!! The second to last time it happened my truck had a STRONG SMELL of something burning but i looked and nothing was burning or leaking (as far as i could see.) When it happens.... I first start to lose power.. Like the RPMS increase but no power is going to the engine.. Then the engine light starts flashing.. Then it starts chugging/deiseling, then i lose vacuum pressure and and no brakes and need to eigher stop or like pump the gas to keep it running. Then when I stop the engine light eventually goes solid and then it runs like normal again. It looks like the plugs may be running a little lean.
Anyway.. I conclude its only when Its reving ariound 2500rpms for more then a few seconds. Its SO scary because when I lose the vacuum pressure I have no brakes and I have almost plowed into cars infront of me a few times.

Does anyone have any suggestions asto what my problem may be?? Im a working college girl and dont have the time to worry about dying when i drive!! haha! Anyway.. Please help me out, any suggestions would be GREAT!!! I'm desprite for ideas. This is becoming B.S! I cant even drive home from my boyfriends house because everytime I go up this hill the damn thing breaks down.

my email is chevy4x4girl@sbcglobal.net and if you could Email me or reply to this and help me out i'd appreciate it!

My first guess would be a fuel delivery problem. Fuel filter or, worse, fuel pump about to go out. This year is noted for lousy fuel pump assemblies. I'd start with a filter.

When was the last time you had a full tune up on the truck?

well with the blazer first of all i dont think you have a coil pack, should be a cap and rotor. thats how mine is. its a 2000. Second the blazer doesnt have fuel injectors it has little springs that need a ceartin amount of pressure to realease and then allowing fuel to pass. so, your fuel pump HAS to be in full operating pressure. wich sucks bc some cars can work with less pressure. so it verry well could be a fuel pump but i wouldnt think so . if you think about it there isnt much more pressure on the fuel pump itself, at least not any more then when you would floor it on flat ground. but there is more stress on the motor. I would take it to a full service shop and have them take a look at it.

When was the last time you had a full tune up on the truck?

What do you mean by full?
i got new plus, wires, coolant flush, rebuilt tranny, oil change, new battary etc.. within the last year

97Blazerct...
What brand of Spark plugs did you put in her? AC Delco Plat's gaped at 0.60...
Did you change the Distributor cap, and rotor? Replace the fuel filter, Air filter, PCV valve? Did you Clean the MAF sensor and screen? What brand of new wires are in the truck right now? Something good I hope, (Not chepo's)
That's all I ment by Full Tune up...

Sounds to me like a vacumn leak, Check the hose to your brake booster and follow it back to the manifold, make sure that the vacumn assembly is fully seated,then check to see if your spark plug wires are fully making contact at the distributor and plugs. Make sure that there isn't a carbon trail on your distributor. Long shot also check your engine ground.

Also replce the ignition switch.

It is the 1997 weakness.

97Blazerct...
What brand of Spark plugs did you put in her? AC Delco Plat's gaped at 0.60...
Did you change the Distributor cap, and rotor? Replace the fuel filter, Air filter, PCV valve? Did you Clean the MAF sensor and screen? What brand of new wires are in the truck right now? Something good I hope, (Not chepo's)
That's all I ment by Full Tune up...

I have AC delco rotor, distributer cap, plus, and wires.. I did the fuel filter, rcharged my K&n, and new PCV... Didnt clean the mass air flow sensor or screen..

When was the last time you changed the cap and rotor?

If your recharging your K&N airfilter, you need to clean the MAF ASAP...
WARNING>>>BE VERY CAREFUL WHEN CLEANING THE MAF,
What brand of Spark plugs did you use and what were they gapped at???

Could be the MAF with a little oil on it.

Brake cleaner and a fine super soft toothbrush should clean the sensor filament wires nicely.

I have AC delco plugs and wires and I dont know what the gap was because my dads friend, whos a GM mechanic, put them in for me..

Wheres the MAF located anyway?

i have a 95 blazer and when i had my cylinder misfire it was my distributor. this backyard mechanic put in on off timing. you can get misfires with a coulple of things. what have you put on the truck and what if anything has gone wrong since youve had it give my some history.

I have AC delco plugs and wires and I dont know what the gap was because my dads friend, whos a GM mechanic, put them in for me..

Wheres the MAF located anyway?

It is the sensor 1/2 way up the air intake assembly between the filter and the throttle body hat.

I'm trying to be sure I'm correctly identifying the MAF on my 2000 Blazer. Can you verifying that for me?

You have the air filter assembly, then immediately after the filter housing a switch with a mesh screen in it and three wires going into it and and then further up the intake hose, you have a two wire sensor.

Is the MAF sensor the last one before the intake with two wires about half way up the intake hose or it is inside the switch with the mesh screen in it?

Sorry if my description isn't perfect. I appreciate the help ....

I'm trying to be sure I'm correctly identifying the MAF on my 2000 Blazer. Can you verifying that for me?

You have the air filter assembly, then immediately after the filter housing a switch with a mesh screen in it and three wires going into it and and then further up the intake hose, you have a two wire sensor.

Is the MAF sensor the last one before the intake with two wires about half way up the intake hose or it is inside the switch with the mesh screen in it?

Sorry if my description isn't perfect. I appreciate the help ....



the MAF is the one with the screen in it. The smaller one is Air Intake Temperature sensor.

if it's throwing codes, try cleaning the MAF with a Q-tip and some spray electric cleaner. be gentle on those wires.

why do you suspect the MAF?

on a 2000, it might be time for new plugs, wires, distributor cap, and PCV valve. clean the throttle body too. have you done any of this recently?

Thanks and yes I've done all that you mentioned about 10K ago. It runs well except for a very sporatic miss at 1500 rpm when going up a small incline but the strange part is, it only does it if I've just exited from an extented highway drive. Then as suddenly as it happened, it's fine after a few minutes and doesn't do it again. I'm having the codes read tommmorrow and there's no check engine light on. Thanks again for your help. I'll start a new thread if the problem continues so I don't infringe on the person who started their own thread.

Thanks and yes I've done all that you mentioned about 10K ago. It runs well except for a very sporatic miss at 1500 rpm when going up a small incline but the strange part is, it only does it if I've just exited from an extented highway drive. Then as suddenly as it happened, it's fine after a few minutes and doesn't do it again. I'm having the codes read tommmorrow and there's no check engine light on. Thanks again for your help. I'll start a new thread if the problem continues so I don't infringe on the person who started their own thread.


have them check for history codes. get the EXACT code.

what brand plugs did you put in. Bosch plugs are crap.

All Delco parts, I'd never use anything other than Delco for those components. I just checked the MAF sensor and it's clean as a whistle.

The problem didn't start right after the tune up, it started about 3k ago. I thought I'd found it one day when I lifted the hood and found the hose laying loose from the MAF sensor. It had been pulling air from the engine compartment and not through the filter. I cleaned the throttle body thoroughly when I found the loose hose and disconnected the battery for 10 minutes to clear any codes but it's still doing it.

The thing is it's so intermittent and only lasts for a few seconds and then it might not happen again till I've driven at highway speeds for over 30 minutes.

Get the code for us.

Without it we can do nothing.

I had it read today and there were no codes

I had it read today and there were no codes


how do you know cylinder 6 if there are no codes?

changed your fuel filter lately? new brand of gas?

did you gap the plugs yourself? to the proper gap?

do you use cruise control for those highway drives? might be a pinhole leak in the vacuum?

Sorry, not sure what you mean by cylinder 6 ... I had the codes read by an auto parts store locally and it came back clean. I watched it read the codes and it went through a whole assortment of checks.

Fuel filter was changed during the tuneup at 10K done by a repair shop. The problem only started about 3K ago but the tuneup was done about 10K ago. No new gas brand and no on the cruise control but it definitely only happens after an extended highway drive.

It's not even during heavy acceleration when it happens, in fact, if I accelerate causing it to kick into 3rd, it stops.

It's when you're going along at say 35 miles and it goes from 3rd into Drive, at around 1500 rpm, it starts to bounce to 1800 rpm and back to 1300 rpm and then as soon as it started, it stops and it's fine.

Thanks for your responses ....

The title of your post is " ... cyl 6 misfire ..."

?

how many miles are on your truck?

you might run a bottle of Techron injector cleaner through the fuel system. Might be a sticky injector poppet. If you really feel like workin', check the gap of the plugs and for anything obvious like a loose boot to the plugs or cap.




Sorry, not sure what you mean by cylinder 6 ... I had the codes read by an auto parts store locally and it came back clean. I watched it read the codes and it went through a whole assortment of checks.

Fuel filter was changed during the tuneup at 10K done by a repair shop. The problem only started about 3K ago but the tuneup was done about 10K ago. No new gas brand and no on the cruise control but it definitely only happens after an extended highway drive.

It's not even during heavy acceleration when it happens, in fact, if I accelerate causing it to kick into 3rd, it stops.

It's when you're going along at say 35 miles and it goes from 3rd into Drive, at around 1500 rpm, it starts to bounce to 1800 rpm and back to 1300 rpm and then as soon as it started, it stops and it's fine.

Thanks for your responses ....

Sorry, I really should start my own thread because this isn't mine. I jumped in this one because I had a similiar problem and it's not the right thing to do. Let me start my own and we'll go from there. I'm a computer programmer and moderate a Windows problems website so I know the problems when people jump into someone else's thread. I apologize.

Sorry, I really should start my own thread because this isn't mine. I jumped in this one because I had a similiar problem and it's not the right thing to do. Let me start my own and we'll go from there. I'm a computer programmer and moderate a Windows problems website so I know the problems when people jump into someone else's thread. I apologize.


oops. just noticed it's not your thread title ...

Ok.. To continue on my neverending problem....

SPECS: 1997 Chevy Blazer LS 4x4 with the 4.3 Vin W..

HISTORY: Everytime I go up a large hill.. Or when my truck rev's at approx 2000rmp's or higher.... This happens..
1. Start to lose power... Hit gas.. No power but engine revs higher.
2. Check engine light starts flashing
3. Truck starts to Bogg/diesel like it is going to stall
4. I lose all vacuum pressure to my brakes a-k-a NO BRAKES (way too scary for me!)
5. When I pull over and get it to roll to a stop... It continues to bog for a minute or so.. while the engine light flashes... Like its dying but has never actually fully died
6. Engine light goes solid, idle goes back to normal and i regain vacuum pressure...

CODE THROWN: This has happened about 10 times to me.. 7 or 8 were all on the same hill.. I've gotten 2 different codes.. Sometimes it is the P0306 - Cylinder 6 misfire and sometimes it is the P0300 - Random/Multiple cyinder misfire

HOW IT RUNS NORMALLY: idles rough sometimes, not bad.. I dont drive it very often because of this problem so that may be why... But overall she runs fine other then when I go up hill or on the highway at higher RPM's.

NEW PARTS/WORK DONE:
-Found dry-rotted vacuum hoses that might have been kinking... Replaced them tonight (and when I went up that hill, i still had the same problem/misfire)
-New plugs, wires, battary and basic tune up in OCt '04 but have only driven a few thousand miles since.
-New cap, rotor, fuel filter..
-oil changed regularly.

Does ANYONE know what my problem could be? I'm DESPRITE and I am running out of ideas.. Has anyone who has had this problem FOUND A SOLUTION?!?!!?

Please please help me out... Email: Chevy4x4girl@sbcglobal.net
Aim: Chevy4x4GiRRL

Thank you guys in advance

Christine

Also.. All new o2 sensors and Y pipe and exhaust

ALSO NEW IGNITIO COiL PACK

Ignition switch, 1997's biggest problem.

You might also want to check fuel pressure.

You might also want to check fuel pressure.
How do I do that??

How do I do that??

With a pressure tester at the test port on the rear right hand side of the engine. If you don't have a pressure tester you should be able to have a machanic do it pretty cheap and it wouldn't take but about 10 minutes to do. For your 97 you should be seeing 58 to 64 with key on not running and running it should decrease 3 to 10 PSI.

Thank you :oP I'll get someone to do it