Throttle / Idle issues

[giardmi09]

Hi,

I have a Beretta z26, 3.1, 6 cylinder with an automatic transmission and about 140,000 miles.

Here is my issue. My car's RPM will rev up really high sometimes, almost always when I park or I'm sitting at a light or stop sign. It happens much more frequently when I start the engine while it is already warm. For instance, I'm driving home from school (30 Miles) then I stop at the store. Ten minutes later when I come out of the store and start the car it usually either stalls out or the RPM will stick very high. I have replaced the IAC valve, EGR valve, and throttle position sensor to no avail. Any help with this would be much appreciated.

Thanks.

Mike

[Money pit Beretta]

Spray some carb cleaner around the upper intake when it's running(normal idle). You may find that the RPM goes up and that would tell you that the gasket is bad. Or you have a vacuum leak somewhere.

[Rettax3]

What year Z? It really does sound like an IAC problem, maybe the wires are bad? Run a continuity check from the IAC's plug and the terminals on the PCM. It is a PITA, but if you can't find a vacuum-leak like money pit suggests, that would be a good next step to take.

[giardmi09]

Thanks for the prompt replies, I really appreciate it.

I'm at work now but as soon as I get a chance I will look into both of your suggestions and get back to you.

Mike

[giardmi09]

Oh and I'm sorry i forgot to mention it is a 1996.

Mike

[giardmi09]

Thanks for your quick responses, It is a 1996. As soon as I'm able I will check for vaccum leaks and get back to you guys.

Thanks

Mike

[Rettax3]

Being a '96, you could also have an issue with the MAF (Mass Airflow Sensor).

[Money pit Beretta]

I agree, clean the MAF with some MAF cleaner. Then post here after you have done all your checks and cleaning.