Help car dies when put in gear
 

I have a 86 volvo 240 with only 68000 miles. When I start the car it runs and drives fine but will die when put in gear. What would cause this? It will idle fine at times but too high sometimes. When the ac is turned on it almost never will stay Idled.
New:
Main fuel pump, check valve
Fuel filter
Coolant temp sensor
New MAF intake boot
Plugs , wires, rotor.
Valves adjusted
Timing belt
Runs perfect I have cleaned the IAC and installed a used MAF
I have a new o2 sensor coming.
Any suggestions?

Nobody experienced this?

'starts and drives fine but dies when put in gear' ? how can it drive fine if it stalls in gear?