1997 Chevy Malibu misfire issue

[Karnage219]

This is my first post so I apologize if it is in the wrong section.

I have a 97 Chevy Malibu V6 3.1L with 92k miles on it, a couple weeks ago i started getting a misfire issue. The car would start to misfire when under heavy load such as accelerating up a hill. The local auto parts store diagnosed it with code P0302(cylinder #2 misfire). I started by replacing all of my spark plugs(ACDelco Platnum) and wires. This seemed to fix the issue for a day or so, after that the misfire worsened. I would misfire at random times and when under heavy loads. This caused my transmission to keep shifting up and down followed by the all to familiar hot/melted plastic smell of overheated transmission fluid. This continued on for a few days as it got worse. The car than started to misfire heavily all the time. I took the car to another auto store and it pulled up codes for Random/multiple misfire. I then took my car to a mechanic for a full diagnostic, their computer said their was a misfire on cylinder #1, as-well as a bad spark plug wire on #1( He found this by getting shocked while wiggling the wires on the coil pack) and told me to replace the bad wire. I replaced all wires again and the problem remained. i took it back up for re-diagnosis and they then said it was a bad coil pack. I replaced the coil packs and the problem still remains. I am not ready to call it quits and have them fix it yet to to lack of funds for this but having my car in working order is critical for my job. If anybody has any idea or a similar issue please help me ASAP.

[Tech II]

I am a little confused here....do you bring in your car to shops, and ask them to diagnose the problem, and then go home and fix it based on what they told you? Do you pay them for this diagnosis?

I assume this is a 3.1/3.4?

Why are you driving this car with a misfire? Do you like paying for damage to your catalytic converter?

[Karnage219]

Sorry a bit of a messy post, i took it to a mechanic who offers a free diagnosis then attempt to fix it off of what they said was wrong because i am broke.

Yes, it is a v6 3.1

I have no choice about driving the car, i am a delivery driver and need my car for my job, i don't have a back up vehicle so its drive this and possibly break it or lose my job.

[DeltaP]

If your car is critical to your job then I would suggest you have it repaired professionally. In this case the car comes before the rent. No car...no job, no job...no rent. Get a several estimates and maybe some recommendations. Compare the work needed as well as the price. Keep drivin it around like that and you wont have a car....no job...no rent.

[Karnage219]

Originally Posted by DeltaP

If your car is critical to your job then I would suggest you have it repaired professionally. In this case the car comes before the rent. No car...no job, no job...no rent. Get a several estimates and maybe some recommendations. Compare the work needed as well as the price. Keep drivin it around like that and you wont have a car....no job...no rent.

Thank you for your opinion, that said i still would like to fix the car myself before I take it in to get done.

[Tech II]

OK, it doesn't misfire at idle?

It doesn't misfire under a light load? It only misfires under a heavy load?

New plugs were used? Properly gapped?

you installed new wires? And then replaced those? Sure you have the right wires going to the right plugs?

You replaced all 3 coils?

Were the coils new?

[Karnage219]

Originally Posted by Tech II

OK, it doesn't misfire at idle?

It doesn't misfire under a light load? It only misfires under a heavy load?

New plugs were used? Properly gapped?

you installed new wires? And then replaced those? Sure you have the right wires going to the right plugs?

You replaced all 3 coils?

Were the coils new?

Sorry, i wasn't very clear, it only misfired under heavy load 2 weeks ago, now it is constant.

Misfires at idle

Brand new ACDelco professional platinum plugs gaped and checked at .060

New wires( one had a manufacturer defect so i replaced all wires again with a brand new set).

Right wires going to right plugs, carefully followed each wire from coil to plug nothing mixed up.

Installed 3 brand new coils, carefully and correctly re-attached wires, checked them for spark. all working properly.

[Tech II]

With all the parts you have put in, you are at the point where you should have gone to a garage to get it fixed....if that CE light has been flashing, you could have damaged the catalytic converter....

Places like AutoZone, are great for reading codes on cars for free....but diagnosis? Forgetaboutit! A monkey can read codes off a scan tool....only a good tech can look at engine data, and interpret it, to develop a good diagnosis....

But you have to stop just installing parts.....I don't think you have the tools to diagnose the problem.....

You need a spark tester, to check the output of each coil terminal(possible ICM).....you need a fuel pressure gauge.....you need a compression gauge to check cylinder compression.....you need a noid light to check injector pulse....you need an ohm meter to check individual injector resistance(possibility of mouse nest under plenum has eaten the insulation off the injector harness(es)).....you need a scan tool to read O2 data, and other engine data....

About the only things I think you can check are, looking for a vac leak, make sure the air filter is clean(not dirty or have a mouse nest), checking the vac line to the fuel pressure regulator for fuel, and also removing the pre O2 sensor(the one between ex manifold and cat), and taking a short quick drive(will be noisy) to see if power has come back.....if car runs ok, your cat is plugged....

[Karnage219]

Originally Posted by Tech II

With all the parts you have put in, you are at the point where you should have gone to a garage to get it fixed....if that CE light has been flashing, you could have damaged the catalytic converter....

Places like AutoZone, are great for reading codes on cars for free....but diagnosis? Forgetaboutit! A monkey can read codes off a scan tool....only a good tech can look at engine data, and interpret it, to develop a good diagnosis....

But you have to stop just installing parts.....I don't think you have the tools to diagnose the problem.....

You need a spark tester, to check the output of each coil terminal(possible ICM).....you need a fuel pressure gauge.....you need a compression gauge to check cylinder compression.....you need a noid light to check injector pulse....you need an ohm meter to check individual injector resistance(possibility of mouse nest under plenum has eaten the insulation off the injector harness(es)).....you need a scan tool to read O2 data, and other engine data....

About the only things I think you can check are, looking for a vac leak, make sure the air filter is clean(not dirty or have a mouse nest), checking the vac line to the fuel pressure regulator for fuel, and also removing the pre O2 sensor(the one between ex manifold and cat), and taking a short quick drive(will be noisy) to see if power has come back.....if car runs ok, your cat is plugged....

Sorry this whole thread is a clusterf**k.

First, i dont care about the cat converter, ill cut the damn thing off, weld on a pipe and sell the thing at the scrap yard for some cash to cover this car.

Second, i originally took my car to get checked at a auto parts store, but after i replaced the plugs and wired i took it to a mechanic to have them diagnose it. They said it was a coil pack and quoted me $150 to replace them. so i spent $75 and replaced them myself. That did not fix the problem, id rather waste $75 for a fix that does nothing than $150. they also wanted to re-replace my plugs and re-re-replace my wires for another $100. So I'm not all gung ho about just telling them to fix it, ill end up with a bill >$500, which i cant afford right now.

So here i am about to run my car for another 10 hour shift with no results or real help from this thread.

[DeltaP]

Tech II = I don't think he knows "real help" when he sees it.

[Karnage219]

Originally Posted by DeltaP

Tech II = I don't think he knows "real help" when he sees it.

Nobody seems to know what broke means.
I do not have the funds to take my car to the shop. I barely have the money to fix it myself. I diagnosed the issue as a clogged fuel injector. $80 to replace it and the gaskets, a few hours work. Mechanic quoted $250. thanks for the help.

/thread

[DeltaP]

I'm sorry for your current situation. Believe me, I knew poor. I came from poverty and I ain't goin back there again. Although sometimes I still find myself a paycheck away. The tools alone can cost you more than the jobs worth. If you re-read TechII's last post he's given you a plethora of diagnostic advice. Why dont you start there and report back.