My Cadillac Stalls when shifting from park. on 1998 Cadillac Seville STS

When the vents or the A/C is shut OFF, the car will go into drive without stalling. The radio seems to have an effect aswell, if it's turned ON, the car will NOT stall when shifting out of park. So I have to drive with the vents off and the radio on to keep it from stalling! Wierd!!! Please help.

Asked by for the 1998 Cadillac Seville STS