aight...my car is acting very weird lately.....when the A/C is not on, my car is fine sometimes....BUT when i turn on my A/C and my car is stopped...it revs itself up and goes down and then revs up again and does this untill i give it some gas....what do you guys think is wrong?
The revs going up and down like 100 - 200rpm with your ac on is normal, it's just the ECU compensating for the AC to keep the revs up as it tkaes quite a bit of energy to rotate that sucker.
__________________ '02 Maxima SE '93 Prelude vtec - sold
Ok, when you remove your pcv valve, that's what the car will do, rev up and down from idle to 1500-2000 rpms.. if your pcv valve is going out(sometimes getting stuck) maybe it's being triggered by the slight increase in rpms from when the AC is on... make sense? In other words, if you haven't replaced your PCV valve in a while, do it, even if it doesn't solve the problem lol.
Yeah, my car used to do this. I replaced the intake air temperature sensor and it fixed this crazy revving, and stalling, and permanent high revving all in one shot. I've heard that you can take the sensor apart and clean some screen as well??? do some searches man, there are tons of threads on this.
The screen he's talking about is the IAC. It's the mechanism on the front of the intake mani with the black cyliinder attached to it and a 2 wire plug on it. Take it off and clean the screen and it'll idle better, but I dunno if that's your problem.
Also, have you don't the 'coolant bypass mod' ? If so, make sure your block off plate isn't leaking air, or your car will have an erratic idle like you have.
you only have a 'block off plate' if you did the coolant bypass mod. If you didn't, then don't worry about it. If you did, and you don't have a block off plate... well, then that's probably your problem, though it should have been a problem from the get go.
AutoForums.com is the premier network of enthusiast-owned
enthusiast-operated automotive communities.
We operate more than 100 automotive forums where our users consult peers for shopping information and advice, and share
experiences and opinions as a community.