On my 94 Z28/LT1 A4 I have this very rough idle (interior shaking) only when I turn my A/C on. When A/C off - idle is normal, A/C on the revs are close to normal but I get the F**CKING SHAKES!! Feels like a loose plug wire.
Where should I look first??

As always thanks all!!

Laterzzz...LA

 

The AC can cause things similar to that, since it's putting a load on the engine/battery and the auto is already at a low idle.

Check your voltage on the battery when you turn it on/off.

Mike

 

Anyone else with this prob???

 

mmmmm.....

 

Nope, I haven't noticed this at all, sometimes my car will shake a little bit at auto, but the A/C never changed anything. I used to drive 120 miles a day in the city during the summer at 100+ days without the 160º thermostat and the A/C on full, no shaking.

I'll look into my manual and tell you what I can find.