I've had various stalling issues over the past year. I have changed out old parts which seemed to solve the problem only to have it return shortly afterwards.
Currently my 240 wagon starts up and drives great. After about 10-15 mins while driving the engine will stall. I checked the plugs and noticed a black, dry soot. I replaced plugs and had the same stalling problem. Pulled one plug and the soot was back.
Here's a list of items replaced...
MAF Sensor
O2 sensor
Crank position sensor
fuel relay
replaced all fuses and cleaned fuse holders
fuel filter & both fuel pumps
plugs/wires/cap & rotor/ oil filter/ oil
fuel pressure regulator
and the power stage (ignition amp),fuel control unit and ECT sensor.
25 amp fuse holder
Most items I have done myself. When I was stumped the wagon went to a local independent Volvo shop.
Last time it went to the shop they replaced the Crank position sensor from IPD which was less than a year old. Also the fuel control unit (silver box under passengers side).
I contacted the Volvo shop and they don't seem interested to trouble shoot my problem.
Any help will be greatly appreciated.