So I did some searching of the forums to find something, but I didn't find anything useful. I have a 1992 firebird 5.0 TBI and just converted from old r-12 to r-134a. I was charging the system, and when the compressor kicks on, my idle jumps to like 1600-1700rpm. The normal idle is somewhere in the 600-700 range. I was going to keep charging the system but I thought an 1000 rpm swing when the AC is turned on is way to high. It cycles when the compressor kicks on and off (I know theres not enough freon to keep the compressor on).

From what I gathered, theres a wire from the compressor that tells the ECM to up the idle like 100rpms, but what would cause it to tell it to jump up that much? The only thing I can think is maybe my compressor is causing excess drag on the engine and causing the huge rpm jump? Any thoughts or suggestions are greatly appreciated.