'99 2.4l Ga

[echoes85]

My grand am starts ok when cold, but i have to give it gas when the engine is hot and i try to start it up. When i warm up the engine, the rpm goes lower to the point that it almost cuts off, but picks up everytime it hits 4-500 rpms. The rpms fluctuate when i have it in drive and am stopped at a light, it starts getting a rough idle and then it smooths out, it keeps doing this until i actually pick up speed. When i accelerate the engine it sort of has trouble picking up speed at first, but then takes off normal. Also when i am going about 60-70 mph and i press the brakes the rpm fluctuates between 700-1500, then it smooths out about the time it gets to 20 or so mph.

I checked the codes and it said P0507 - idle control system, rpm higher than normal.

I checked and replaced the IAC valve, but it still continues to do the same thing and the same code continues to pop up.

the dashboard lights have the "SES" and the "Trac off" lights on and the "Trac off" light blinks when the engine almost dies when im at a light.

[GTP Dad]

If you changed the IAC and the problem continues, remove and clean the throttle body with throttle body cleaner. The area where the IAC allows air into the throttle body may be blocked with carbon and you may not be getting good flow. One other thing to check for is a vacuum leak. Usually this can cause high idle but it can cause rpm fluctuations. I would start with the area around the IAC.

As for the trac light coming on that is due to a low voltage condition due to the engine rpm drop. Once you correct the other issue that should go away.

Finally, have the fuel pressure checked when the car is hot. Sometimes the regulator will malfuntion and cause this issue. That is why you need to pump the gas to start it when hot.

[echoes85]

I haven't been able to check for leaks, i was wating till this weekend to go back home and let my dad check, but now there are more problems. Two days ago the battery light would come on and then go off, and today the whole dashboard went off, the ABS came on, security light, manual brake and the air bag light blinks. the battery is low, because i tried to put up my window and it was really slow

The engine changes first gear very rough when i step on the pedal, the other gear shifts are less rough, but still noticeable.

I checked the codes again and this time another code came up P0172 - the system too rich (bank1), aside from the initial code P0507 - rpm too high, idle control sytem. I don't know what to do now.

[Bassasasin]

Sounds like an alternator connector field wire has gotten loose or rusted...
Check the connectors for clenliness and the wire to connector for rust. They sometimes gets rust between the wire and the end connector.

If you get the voltage and current cleaned up you may see many problems dissappear.



Good Luck

[echoes85]

It turns out the alternator was bad, because the car wouldn't start anymore and i got the alternator checked and replaced it.

Now it seems that the engine runs ok, but the muffler is letting out white smoke and it smells gasoline. My dad said that it was that the should clear up after letting the engine run a while, but i let it run a few minutes and the muffler is still letting a little white smoke with water dripping out.

Also when i put it in drive the rpm still goes down to about 600, but it doesn't want to cut off anymore and it runs smooth. the trac off light is still on.

Also the original code P0507 is still there.