a/c question

[dbleb88]

On my 98 LSC the a/c works fine on max a/c. When I use the automatic setting the clutch cycles quickly and the engine runs rough at idle like it has a vacuum leak. Swapping it back to max a/c it smooths right out and clutch operates normal for hours no problem. Any thoughts where to go looking ? Thanx Bruce

 

[GMAN]

First, do some troubleshooting. You gave yourself the first clue. If you suspect a vacuum leak, then check that. Check it under the hood, and check your connections behind the unit itself.