AC on = slow RPM fall-off

[mojo_monkey]

Hello all,

Car in question is a 1990 325is, 5 speed. When I have my AC compressor on, my RPMs drop off VERY slow. For example, if I'm at 3k rpm and shift from 4th to 5th, even with a slow, lazy, gear change, my RPMs might fall about 200 RPMs between shifts.

Furthermore, when the AC compressor is on, it almost acts like a cruise control is turned on. Again, if in 4th gear at 3k rpm and I lift off the throttle, the car decelerates VERY slowly, if at all.

What's the deal? Anyone know likely candidates for what needs to be replaced or evaluated?

[KenC]

Mine does the same thing, but not to that extent.

[MattM]

the AC compressor adds more resistance to the engine turning.....if you turn any cars AC on the rpm will fluctuate(modern cars computers compensate by opening the throttle slighty)