Diagnosing 1992 Olds 88

[cromanyak3]

I recently purchased a 1992 Olds 88 Royale. It will run fine at first then it will start to sputter and stall, mostly when I come to a stop. It has trouble starting again right away but when it does it seems fine again. I'm not sure if its bad gas from sitting or its not getting spark. I let it run just idling and I couldn't get it to do it, so it only happens while driving. Can anyone help me?

Chris

[maxwedge]

Check fuel pressure , when it won't start do you have spark, How long was it laying up?

[cromanyak3]

It starts right back up it just take more cranking. It sat for a few months I'm sure. Don't know exactly how long. What all parts can be tested for spark. Coils, ecu, etc?

What could cause it to go back to running fine again after it dies and I start it back up?

[maxwedge]

Maybe things cool down for one, maybe the egr sticks open, if so equpped, dirty throttle body, slow functioning iac to name just some.

[cromanyak3]

I had an 88 bonneville with an egr that did that. I didn't see one on this. Sorry if its a dumb question but what's an iac? My girlfriend drove the car home about 30 miles and it never messed up till we were almost there. That's why I was thinking maybe it was the gas.

Does anyone know if there are any write-ups online that tell how to test various parts? I need a haynes manual, but I don't have the money right now, and I'd like to try to figure this out before the weekend is over.

[maxwedge]

idle air control on the throttle body. You may not have an egr on that engine, also clean the throttle body.

[cromanyak3]

I'll clean the throttle body tomorrow and see if that helps. Is there a way to test the IAC? I put some seafoam in and ran it till it got warm, but no luck. I did notice though that when it gets hot the rpm's fluctuate while idling.I'm guessing that's a related symptom. It doesn't do that when I first start it.

I tried the paperclip trick to read the codes but when I put the jumper on it made the engine fan kick on. I don't think that's supposed to happen?

[cromanyak3]

I cleaned the TB and the IAC and its still the same. Not quite sure where to go from here. Is it possible the IAC is just bad? Is there a way to tell? It would be a hell of alot easier to diagnose if it did it all the time. As soon as it dies and I start it back up it seems fine again.

[maxwedge]

If you can kep it running when it wants to stall with a slight amount of gas, this can point to the iac.

[cromanyak3]

No way to test the IAC though? I just hate buying a 60 dollar part when that might not be it. Would reading the codes help? I tried the paperclip trick but for some reason when I jumped A and B it made the fan kick on.

[maxwedge]

Fan kick on is normal when checking codes. You could pull the iac and see if the pintle assy is loose or heavily carboned up.

[cromanyak3]

The end of it where the spring is was a little loose, and the whole thing was very carboned up. I sprayed carb cleaner on it and let it soak, but it didn't seem to make a difference.