have a 96 850 turbo. when i run my air cond. as long as its in park it will run fine. BUT, when i put it in drive the car will cut off and will not start back right away. and when im driven if i come to a stop for a small period of time, it will try to cut off some time it will cut off. as long as im going down the road everything is fine. please help!!

 

Sounds like a vacuum leak, does the A/C work fine other wise?. If so check all the vacuum elbows, hoses etc. A vacuum leak will cause a bad idle. Coupled with the added load of the A/C compressor (as much as 5HP) will make the car stall. My advice is to look at this problem as a bad idle problem.
Check the Idle air Control valve under the black cover at the throttle body. Make sure you hear or feel it vibrate at idle. From that vacuum tee trace all the lines and check the elbows and lines for cracks.

When was the last time you had a tune-up?

Are you getting a Check Engine Light?