ok so I notice when the a/c is on and the car is stopped...the idle is smooth....bout 650 rpm........however when the a/c is off and i'm stopped.....idle is about 500rpm but idling very rough......does this make any sense?

thanks dudes....

 

you need to adjust your Idle Air Controller or just bump up your idle at the throttle cable.

when you turn on the A/c the ecu tell the IAC to let more air into the manifold raising the idle
atleast your IAC seems to be working, there about $250.. with employee discount from Nissan

 

Start with the basics, any rough idle is usually attributed by having dirty/faulty parts. I would say to clean the following items with Throttle Body Cleaner:

IAC (Idle Air Control) As Well as the tube leading to it. (You can also adjust idle here if it needs to be upped through the phillips head screw on the top)

Throttle Body
Lower Intake Manifold

You can also sea-foam your car by Sucking up around 5oz or so through the vacuum line while the car is running, shutting the car off for 10 minutes, then re-start and "blast" the carbon deposits out through your exhaust.

You may also want to try cleaning your MAF With either Electrical Contact Cleaner, Or MAF Cleaner (I'm convinced they're the same thing; both made by CRC)

If none of this remedies the problem, Make sure all spark plugs, and ignition wires are in working order and are not arcing.

Check to make sure all belts are tight and functioning properly, add dressing if needed.

 

really, you probaley just need to adjust your idle

 

I got a question, when my AC turns ON I notice a HUGE difference in my Idle. I know that it's extra load on the engine, but it's really noticable. Does anyone think that I need to replace the compressor?

Sorry for jacking the thread....but the topic is related

 

What so you mean by a "huge difference"?

High idle/low idle/stumbly idle/erratic idle?

 

MIne use to bog hard when i put the A/c on, I replaced the IAC, problem solved.

 

Hello! I guess a lot of people have questions about this topic, I'm one of them, I've always ignored how to adjust the idle, and how to know if your idle is incorrectly adjusted. My car shakes a little bit on D with the brake pedal depressed but never shakes on N or P unless I turn on A/C, I would like to check my idle but I don't know how and I don't know if that would solve the problem. BTW I recently changed all filters (air,oil,fuel) and cleaned the intake and the shake is still there, not much but easy to notice when I'm waiting at a red light.

 

How do u clean the Idle Air Controller and should i check the spark plugs wires first before i should put my idle up. Cause my idle sucks also and when i turn the ac on its goes to some what 700-750 which is pretty cool i love driving with ac in traffic lol. Back to the topic you guys think i should put my idle up? How does it get ruined?