i have a 2005 dodge neon 2.0 that when i am at a stop sign or light the rpm drops from 800 to about 550. i just bought the car and it didnt do it then but now it is. i have replace the plugs, wires, pcv valve,all motor mounts except the engine tranny mount. please help. thanks

 

You might want to check your vacuum lines for leaks (youtube tips). Off the air filter box you might look at your idle air control (IAC) to make sure it's clean of carbron buildup and working. Remove and clean with brake cleaner and qtips.

 

i used ether to try to find vacume leaks and i couldnt find any unless i missed something. the IAC i replaced like a month ago. i will look into youtube for finding vacume leaks. i had a dodge dealer look at it and they said its not running rough but i know it was. they didnt even hook it up to their diagnostic machine to check things. im just stumpped on what it can be

 

One thing I hate about newer cars too many places something can go wrong. Did you run a code reader? May point to O2 sensor or some other fault.

 

no codes at all i am thinking of getting a O2 sensor anyway to put in. could it be my computer?

 

If this happens when gear is in D and AC is off then it's normal for a Neon. Try with AC on and suddenly you have no low rpm problem on red lights.

 

Isn't there some kind of sensor that revs. the engine when the a/c kicks in?