89 celica hesitatin w/ a/c on

[Jerome]

Ok. I inherited this car from my mother. She gave it to me so that I would have something to drive before I go to basic training (previous car was a Nissan 240sx, so I know nothing about this car). Well, when I first got the car, I did a general tune-up (plugs: NGK, cap, wires, rotor, air filter, etc). Well, it ran like a champ. I then repaired the a/c (system was completely empty). It ran for a week or so perfectly. It had ice cold air (which is nice for our humid GA summers).

Well, last week it started hesitating... Its a steady hesitation that occurs anytime the a/c is engaged. It does it while accelerating, decelerating, and has a rough idle (but ONLY when the a/c is engaged). My first thoughts were that the a/c compressor was trying to lock up. But, it still blows cold air and I'm sure it would have locked up completely by now (but it hasn't). So, does anyone have any recommendations?

thanks in advance,
jerome

[allblackalltrac]

When you engage your a/c your esenstially putting more load on the motor...the a/c compressor acts as a parasitic lose engaged or disengaged. The pulley is always turning with the motor its only when you hit the a/c button that it engages the clutch and circulates the freon.
Some things to remember are: you'll always make less HP with a/c, you'll consume more fuel with a/c, you put more load on the motor potentially causing it to prematurelly wear the bearings or over heat the vehicle.
On a hot summer day the car is already at the point of over heating so the ecu pulls timing and dumps a shit load of fuel to try and prevent the motor from detonating. The more fuel it adds the cooler it'll run. Why do you think you get worse gas mileage during the summer than during the winter? Couple that with the fact you have your a/c full blast in bumper to bumper traffic and you know why you see people on the side of the road with their hood up and steam pouring out from their engine bay cause they over heated.
Your problem sounds like you need to adjust the a/c idle up screw. It is a big plastic looking adjustment screw that is bolted to the intake manifold. After you have gotten the car up to op. temp. turn on the a/c and adjust the screw till out idle comes up to 900-1000RPM.
You might want to also check and re-check all vacumm hoses in the engine compartment. If you can afford it run premium gas during the summer and if your in traffic try not to use your a/c.