Contour Enthusiasts Group Archives Forums General Troubleshooting car runs oddly with a/c

i've noticed there's been a lot of threads recently related to a/c problems, but i couldnt seem to find anything relating to my situation.

I feel like my SVT runs completely different with the a/c on. I know the belt is under more strain because it has to actually use the a/c part, but it seems to be causing a lot more strain than it should. Acceleration, especially at lower rpm's, is extremely sluggish.. Only way i can describe it is that its as if im towing a boat behind my car. Rev's in between shifts also dive drastically right away, and sometimes drop below 500 rpms and will stall if i dont give it some gas.

Most automatic cars ive been in dont seem to have any change in pedal feel or anything with the a/c switched on. I dont think ive ever witnessed this in any other car.

i just had a brand new iac put in like last year, so i wouldnt think it would be too bad yet?

...plus i dont think this is related to a rough idle...ive experience that before, and it doesnt seem similar.

Losing notable power is normal when the a/c is on. The idle should not threaten to stall. Check if the cooling fans are running, if one went out or runs slow, the a/c system pressure will rise and put more load on the engine. If the fan does not work at all, the a/c would vent refrigerant as well as making the engine overheat.

Check your accumulator ... surrounded in foam which holds moisture and rots out. THis causes constant cycling which will give you wildly jumping idles.

What you described is exactly what I am dealing with right now as well. I have done many searches trying to find an answer to this problem. I cleaned the IAC and the problem came back about a week later. I just bought a new IAC this evening and will install tomorrow. I did read somewhere that if you have done the TH fix your hole diameter may be too small. I remember a few years ago when I did this fix I had to keep enlarging the hole. I will remove the TH fix and see how that plays out. But definetely, the car runs very poorly with the A/C on. I just installed new fuel filter, air filter, cleaned MAF, cleaned TB, all new O2 sensors, and no vacuum leaks. New IAC is next. Other than that, I am stumped??