Volvo Repair: 1999 volvo s80 with 2 problems, throtle body, volvo s80

Question
Hi we have a 1999 volvo s80 that intermittantly will die when at a stop (ie red light or stop sign) it used to be if the ac was on it would keep the rpms high enough to keep it from stalling out but doesn't always help anymore and at times it will die while driving.

Also, the coolant light comes on about every 300 miles, we fill the resivour up each time and there is no sign of a leak. Where is the coolant going?

Answer
Melissa, there is a leak somewhere.  A coolant system pressure test would need to be performed to see where its leaking.  The stall may be a few things.  An air mass meter, or a possible throtle body issue.  Car would need to be scanned for proper diagnosis.  Roger