Rough idle and vibration with A/C on

[mcox8051]

I recently had to remove the intake on my '96 LT4 Grand Sport due to a rocker arm issue. I had one come off a valve and I took the intake off to replace the lifter. When I got it all back together and fired it up yesterday, the car ran beautifully. BUT when I turn on the A/C there is a very noticeable drag (loss of power) and vibration on the engine. It did not do this before so I think I don't have something back together right. Is this a vacuum issue? Electrical? What happens when you kick the A/C on, what tells what to compensate? Idle/air mixture, timing, ? Someone in another forum mentioned I should check the A/C pressure. I just had it repaired a couple of months ago, a shrader valve was bad and it leaked out all the freon. It works perfectly and is ice cold. It seems like if there were too much refrig added it would have been a problem back then. Since it has happened now after having the intake off, I'm assuming it has to do with that. Any help greatly appreciated.

[c4c5specialist]

HI there,

The PCM compensates for the AC command request and thus raises idle speed to avoid stalling the engine when the AC compressor is engaged.

If you can access data from the PCM, I would be looking at the IAC or idle air control counts to see if it is being raised.

Is it possible they did not put in any refrigerant oil when they recharged the system ????

Other than that, your PCM data will tell you more.

Allthebest, c4c5