2001 Altima 2.4l idle problem
 

Recently bought this veh., history unknown, 90k mi. Quiet motor and trans. Engine routinely runs 900-950 rpm, A/C on or off, though sometimes drops to abt. 650 rpm. Had a similar prob on a 96 Escort, resolved w. new TPS per Haynes manual reco.My gut tells methis isn't quite the same prob.or quick fix. My internet mining uncovered other possibilities so must put together a logical approach versus throwing $$ at it. Intake gasket leak?---expensive labor. TPS, $110, but Haynes says I need a multimeter to set it in the correct position (Escort was a bolt-on). Idle control valve &gasket---$175 + labor. MAF?---didn't check pricing. Note that the CEL has not been lit so I don't know if system is throwing codes. I'm usually anti-dealer but do you think I should just take it in for a plug-in diagnostic?Due to the 90k mi. I figured it needs O2 sensors also. The other issue (a complaint I've read about) is the poor mileage. Just checked it and got 21mpg......and I'm an easy driving slow poke. Any other possibilities for all this? Need a plan of action ASAP. Thx----DWG

RE: 2001 Altima 2.4l idle problem
 

well im pretty sure its not your tps or maf, and if it was an intake leak it would rev up and down all the time, my educated guess with out looking at the car would have to say the idle air control is the problem, also a simple test to make sure your cel light bulb isnt blown is by turning your key on and engine off and the cel light should come on if not the bulb is bad and there is probably CEL codes stored. let us know what you find out.

To make sure that you can manipulate your engine's idle speed to your advantage, you need the help of a working Idle Control Valve. This valve regulates the flow of substances inside your engine to increase or decrease its idle speed.