Engine Problems

[stevemainian]

Started it up one afternoon and it sounded like it was only running on 5 cylinders, and the car would almost cut off, but then suddenly the rpms would jump back up, then start to fall, then jump back up again.

Figured a spark plug wasnt firing, so had a full tune up (plugs and wires replaced) and I had the valve gaskets replaced also. Got the car back, engine sounds fine but would cut off every time I come to a stop after the car has been running after about 10 or 15 minutes. Had them run codes, CPS was bad, O2 sensors were bad, and MAF was bad. Had all those replaced, and its EVEN worse now! Now after 10 minutes of running, it will ALWAYS cut off when the car is at idle, as before it only happened at random times. Please help!

EGR valve maybe?

 

[Black89SHO]

Did you cheak the alternator. The rpm's will be up and down when the alternator is going. In my experience anyways.

 

[SHOZ123]

Power plug at the coil?

 

[V6&V8SHO]

I had an experiance where my car felt like it had 5 cylinders. A bottle of octane boost cured the problem, along with a fresh tank of 93. I mustve ran into a bad tank of 89.

 

[stevemainian]

Did you cheak the alternator. The rpm's will be up and down when the alternator is going. In my experience anyways.

It will only happen after the car is warmed up. And it will randomly happen. after its warmed up. Sometimes when you stop it cuts off, sometimes it dont.

okay, CPS, MAF. and o2 sensors HAVE not been replaced. However, the EGR valve sensor has been replaced.

 

[trueSHO]

Mine did the RPM thing, jumping up and down. After a while it would die at a stoplight. I replaced the Mass Air Flow sensor and haven't had a problem since. Perfect time to upgrade.

Edit..
I'm a *****, didn't read the rest of your post.

 

[trueSHO]

Wait, were they replced or not??? I'm cofused now

 

[Camarok]

IAC???? (idle air control valve... do a search)

It's a cheep cheep alternative to what its sounding like it could be... get yourself a 5mm socket adaptor for a 1/4" drive, and lots of extentions and 2 u joints.... carb cleaner.... and some q-tips. g/l man

 

[stevemainian]

MAf has not been replaced. Im pretty sure the MAF is causing it. When you unplug the MAF, nothing happens to the rpms/idle. So obviously it must not be working.

 

[Denny]

Have you reset the computer and tried running codes again?

 

[luckyGAT]

Is the maf oily from k&n?

 

[stevemainian]

Have you reset the computer and tried running codes again?

Yea.

I don't have a k&n filter.

 

[Slo-Sho]

Sounds like a leaky injector to me. Have you run a cylinder balance test?

 

[SHO_Driver]

MAf has not been replaced. Im pretty sure the MAF is causing it. When you unplug the MAF, nothing happens to the rpms/idle. So obviously it must not be working.

Not necessarily. How does it drive with the MAF unplugged? Same stalling or better?

 

[TankII]

The key here is when warm. DIS.

TankII

 

[stevemainian]

The key here is when warm. DIS.

TankII

We already came to the conclusion thats its not the DIS. Were 99% sure of that.

With the EGR sensor replaced, it seems to work better, but sometimes RPMS will start moving around, and it kinda scares me.

My new MAF will be here today.

 

[jelloslug]

I had a similar problem and it turned out to be a bad ground to the intake. It caused the DIS to not function properly.

 

[TankII]

I was 90% sure it wasn't my DIS, but it was.
Check your CATs. If they are turning Red from running lean while it is running on 5 cyl, it's the DIS.

Borrow one from someone and see if it solves your problems. That's how I found it was my DIS.

TankII

 

[qiksho]

Clear the codes....and then run it till it dies again.

Then run the codes - the CPS can/and will cause the car to die after warming up. This is usually caused by a leaking water pump. Are you leaking coolant?

From my experiences a bad maf, and o2's will not cause the car to die. You will however get very bad gas mileage. You can run with the MAF unplugged if you think it is your culprit, this will throw a CE light though. By doing this the computer defaults to standard readings for that sensor, so you will run a little rich.

 

[freqsho91]

My car's idle is fluxuating 800 to 1500 at start-up. I have to let it warm up before pulling away and after it warms up sometimes and the key word being "sometimes" when I change gears the motor revs. The motor runs fine with great power while clutch is disengaged when warm although while cold I have to keep working the clutch to keep it from stalling. I have a 91' with 3.2L. upgrade and stage III perf. pack. heads rebuilt