i have a RPM problem. when my car is idling the idle fluctuates really bad. also if i come to a stop from reverse or if i rev my car the idle drops to 400 and then goes up and keeps going back down until it finds itself. idk what the problem is. also the dealer said they couldnt find out the problem. i put the stock intake on and it still doin it. its actually doing it worse with the stock intake on instead of the after market intake. so idk. someone tell me what it might be.

 

Could be a dirty MAF, this also might be related to your poor mpg thread