When i turn my a/c on the idle bounces up and down, constantly.... not just wen i turn it on, but the whole time the a/c is on.... Up and down up and down... Any ideas?...... ( vent works fine )

 

sounds like normal operation. when the compressor is on the idle is raised to compansate the load that the compressor puts on the engine. and when it turns off the idle returns to normal. sounds to me like its working fine. where is the rpm fluctuating around?

although if the rpm's arefluctuating fast like every second or so the refrigerant may be low. causing it to cycle fast

 

constantly like to the point where it sounds like there is some kind of "cam" almost rev? dont have that on my stang but my third gen fbody does the same thing and i could never figure it out i figure its the AC clutch or something like that that wont fully engage,

 

no it is def not normal... im talking like 1500 rpms and dropping to 200 ( almost stalling ) then back up to 1500 then back down to 200..... over and over and over...and when it is on when the car is moving the car will sputter... but as soon as i shut it off, the car runs fine.

 

sounds like your low on freon... thats a sign ive heard...