I bought this truck 2 yrs ago and it has a problem idling, its rough and stays around 600 rpm but then drops to 350. Everytime i stop at lights or signs, is falls to 350 and then comes back up to 600. But sometimes it stalls out after revving. I Cleaned my throttle body, and cleaned IACV. What else can be done to resolve this problem?
Bad IACV sensor?
Bad pcm/ecu?
Bad throttle body?
Fuel injectors/pump?