1994 Pontiac Bonneville

check for a faulty PCV valve first, test it by shaking it, if it doesnt rattle its bad.

next check for vaccum leaks. take a can of carb cleaner and spray around all gaskets and vaccum hoses with engine running, if idle changes youve found a leak.

Well no vaccum leaks>

clean out the throttle body, it may be plugged, also the EGR valve could be sticking causing it to run faster.

I have done all this thottle body is clean.EGR valve is working?It idles about 1500 Rpms and sometimes gets higher and sometimes goes down when it gets hotter but not much. I don' t know what esle to do????

can you manually adjust the idle level by turning an adjusting bolt or screw? maybe throttle cable is tight and needs adjusting.

a smoketest is the best way to find a vaccum leak.

The flap on the thottle body closes all the way.

There may or may not be a idle adjust screw somewhere near where the accelerator cable hooks to the throttle body, that may be screwed in to far.

No screws. Sometimes I start it and it idles up real fast.I can turn the car off and start it back up and it idles back down to normal. I just don't know what to do .

will idle come down by itself if you dont turn it off and restart?

No ,the idle usually keeps getting higher and higher. Even sometimes when I restart it. It doesn't go down. It might do good all day and then all at once start idling crazy. I think I'm going to set it on fire.

sounds like the IAC module, my first prediction, did you say you already replaced it?

it could be the ECM controling it improperly, check the harness from the IAC module all the way back.

in addition to previous posters suggestions, double check and make sure that u purchased and installed the correct IAC for your specific model, year, etc. It's not likely that an incorrect IAC would have the same connections but I've seen it happen and the problem really sounds like your IAC. Also take a look @ your Mass Air Flow sensor. Usually a bad MAF would just cause the car to stall but a dirty one might cause it to freak out. Lastly, you may have a bad fuel pressure regulator. You can check it by attaching a fuel pressure gauge to the schrader valve on the fuel rail and turn the ignition w/o cranking the engine. Your psi should be about 40-43 psi. If it's higher it could be your FPR letting the fuel pump go nuts, hence the high idle.

I finally checked the TPS with my voltage meter And it was reading wild. It is supposed to read about .5 volts with the Throttle closed, it was reading 2 volts. I would move the throttle like giving it gas and the voltage would jump around everywhere. It has 5 volts coming to it and should have 5 volts going out with the throttle wide open. I just want everybody know just in case someone else had these same problems. Plus the transmission gears didn't change right. Thanks for all the Emails trying to help.

thank you for posting back and i can gaurentee this will help someone!