When I put the car in gear (Infiniti G-20), it idles / runs rough. This is exacerbated when the A/C is turned on. Since I'm in Texas, A/C is a must. Any ideas on what could be causing this? May not be related, but the A/C has recently started acting up (no cold air, but if I turn the A/C off and right back on, it is fine).

I would appreciate any help.

Rudy

Sounds like it could be the idle air control valve. IACV. this is located on the inlet mainfold on the left hand side . it will regulate the idle when a load signal is applied. you could try removing and cleaning failing that replace it.

Thanks for the suggestion. I'll check it out.

Sorry for digging up this old thread.. I experience the same rough idle problem on my SR20DE especially when shifting into D or R more so with A/C on. When engaging to R, it is usually sharp and I can actually feel a light "thud" backward.

I have recently serviced the IACV unit (along with throttle body cleaning, new vacuum hoses, new dist cap & rotor, plug wires, new motor mounts etc.) but it did not get rid of this problem..:(

I am basically at a dead end and at the same time frustrated.. thinking of replacing the IACV. My question is in IACV unit, there's an AAC valve and there is a FICD solenoid.. can i replace them separately or the entire IACV needs to go ?

Any help or pointers really appreciated. Thanks guys.