I just got my A/C working again, and yesterday was pretty hot out, so when I was out driving around in town the car was running a little hotter than normal when the A/C was on ... between 200-220ish which is still fine as far as I'm concerned. But I noticed something new I have never seen before ... when it was up towards the 220ish range the car doesn't idle for crap ... it constantly revs up and down between normal idle speed and about 1500. Now I heard somewhere that the PFC actually does this on purpose to somehow help the car cool down faster or something, but I can't find any info on it. Is this true, or do I have a bad sensor somewhere or something??

 

It's gotta be a PFC setting. I have the same surging idle when my a/c is on too. I'd like to know what the "fix' is too.

 

Anyone? I know the PFC has some settings that apply when the coolant is cold, but what about this funny rev thing when it's hot??

 

Maybe your ISC (Idle Speed Control) solenoid is sticking at it gets hot....

 

Mine does the same thing...as does a few other peeps around me. i was told that the pfc is learning the new requirements placed on it. If i sit there for a few minutes it will level out until i start driving again. After a few hours of this sort of thing in everyday driving, it will "learn" and cut that crap out.

Mine is getting better everyday but is still annoying a heck.

The other option is to have a tuner dial it in better..but eventually it will level out...at least thats what i am hoping.

 

Hello.

 

I have the same problem. I unplugged the ISC and the car does not bounce when it gets hot anymore. The ISC was buzzing, so it must be stuck.

 

mine started doing that yesterday; I was thinking of yanking the battery power for a while and seeing if it would reset, but if it's something that only goes away with time, I'll ride it out. car was pretty cool (83 deg, only running for about ten minutes), so i doubt it's heat-related.