Hi Again,

I was on here about 3 weeks ago complaining about my 94 z28 misfiring and running very rough as almost as if it was going to stall out. I've been having problems with it all summer since I got it out of storage. Now I'm looking for any ideas that may help me in easy terms. First off I had the water pump and cap and rotar replaced because it was leaking, ok, that fixed the water problem. Now I am on to where its running rough especially when it comes to a stop at a light and is sitting still. It starts to chug and sputter. And it would almost misfire alot... So about 2 weeks ago I had the Distributor replaced, which helped my misfiring alot, it still did not solve my problem though.

I noticed now its only doing it when I drive it cold in the morning and let the temp get up to about the first notch. Once the temp gets up and I go inside for about 30 minutes and go back outside to go somewhere it starts sputtering and just running crappy all around. Then once you step on it real quick it will almost clear itself out and be fine until it sits again. I guess my problem could be worst but Im just looking for any ideas what it could be. My father thinks it might be that its almost like getting too much fuel at one time because its warm? (thats just a guess)

I think my next guess will be to get my spark plugs and wires checked, I even thought about the O2 sensors too. I do agree all the work I've had done so far as made my car run even better so I guess it wasnt all pointless.

Any other suggestions would be greatly appreciated.

Thanks

 

Is the check engine lite on? Also check the IAT sensor, ECT sensor, and both O2 sensors. Also, temporarily disconnect the wires from the MAF sensor, to force the engine into open loop mode (it wiil bring up the check engine lite, but ignore for the test), and see if it runs better in this condition. I suspect the engine is running bad when it goes into the closed loop mode, which idicates a bad sensor is coming into play.

 

You may want to investigate the catalytic converter. I was stumped for weeks with a similar problem (no codes appeared on a scanner) until I had the converter replaced. However, they are pricey.. $600 from the dealer or about $450 from on-line shops