2500HD4x4

1993 GT, manual transmission. Everything runs great until I hit the AC, then the RPMS drop below 500 and struggle to stay running. Turn the AC off and immediately the RPMs jump back up. This does not happen if I am moving, but when the vehicle is stopped or the clutch is depressed (a true idle), the RPMs get scary low. I'm sure this is something simple, just would be nice to have AC in Georgia. Thanks.

__________________
1998 Silverado 2500HD
5.7L - 4x4 w/ Eaton Locking Diff
348,000 MILES

1993 Silverado 2500
5.7L - 4x4 w/ Eaton Locking Diff
449,000 MILES

RADTOY

I had a similar problem with my 2000 Tundra. Slowly the problem got worse until, I had to hold the throttle down just to keep idle with or with out hte air. It turned out to be dirty fuel injectors. Hope this helps!

inafogg

not sure if its still being used but you may have an idle solinoid thats energized when the ac is turned on.if so it will be located where the idle screw is.