Hello, new here, I was told the rpm will jump some when the compressor kicks on, but while on a 4 hour trip my tach jumped up about 500rpm,then down, up , down , up, at least 6 times in about 15 seconds. It did this a few times during the trip. Something to worry about? Only 24000 miles on my 03 GT.

I had a 96 cavalier Z24 that did this and a few months later the dealer said the tranny was terminally ill and each time it did the jump they heards a "grind" in the trans. They coudln't say what it was without taking apart. That car wasn't worth fixing at 200k on it.

Thats a new one on me. Hopefully someone else can help you. Please keep the information coming. Welcome to the board.

Sounds a little like the Torque Converter didn't know whether or not to stay locked. If the a/c was on the pcm may have been having a hard time trying to determine the engine load.

Sorry to say, but I'm more inclined to say tranny, but you'd have to get it checked out to say for sure. 24k is a bit low on the mileage factor for the tranny to go, but I've seem 'em go with less miles on the car.

Well, the only other thing I know is (and this leads me to believe the AC compressor is part of the cause) we just had 2 AC leaks fixed which had caused the dual climate to only blow cold out of the passenger side. Dealer said that was due to the parts being closer to those vents so they stayed cold even though it was low on R13 or whatever they used in 03.

Second problem occured at the same time the "jumping tach" did, that was or cruise quit working. Took it to the dealer thinking they messed it up while fixing the AC (just a hunch). They determined some sort of brake switch was causing the cruise to fail (the brake pedal was leaving itself partly down).

All three of these things occured last week. The AC leaks were probably there since we bought the car in December. But fixing them, then driving to Milwaukee from Owatonna at 75/80mph with AC running kicked all this off, it was about 90 degrees outside.
If the (computer?) can't tell where to put the torque converter because of the AC, will it learn?
If this ends up like the Z24 did I may need a new trans, and it doesn't seem like its the trans's fault.
We drove the one hour freeway, one way daily commute last night and had no problems, it seems to be sporatic that way.

Low transmission fluid can cause your torque converter not to stay locked. You'll probably set a code after a while of this. Check your fluid.

MAF ???

Mass Air Flow Sensor. It's on the intake tube going from your air cleaner (whether its a cone or box) to the intake manifold.

I'm going with torque converter/tranny related issues. My car does this occasionally and my tranny is messed up big time...

No idiot lights lit, so can't be MAF or anything right?
Where can trans fluid go to make it low, the dealer said only on the floor from a leak, I have no leaks.

I think that would be the Air Intake Temp sensor.

I believe the MAF is the black box thing on the top of the front of the throttle body.

MAF can still act up even though the MIL does not set

yep

I would check to see if your throwing any codes before I go crazy chasing parts. My car did this one time and it ended up being a spark plug wire.

I was always told I need to have an idiot light on to be thowing a code. Are there places that will code check for free?

Autozone will check for free.

I have a strange A./C rpm problem also. When I am coming to a stop, say to go up my driveway and I turn the A/C knob to off, my rpms sore to 2,000 and my car wants to take off on its own. Lasts like 10 seconds then goes back to idle. Has happened about dozen times now, in the past few months.