850 turbo stalls every time when warm. 150,000 miles, all maintenance to date, running perfect until one month ago. Now at local non factory Volvo repair for four weeks. They can not figure it out. Throttle relay replaced, cam sensor, ignition, fuel pressure, plugs, wires all checked OK. Starts perfect, warms up, engine stalls for seconds every minute, whether giving gas, coasting etc. Finally stalls and will not start until cold. When not stalling runs perfect (it actually kicks butt).

Factory Volvo repairman came to help and also ran all codes and can not figure it out. Said it will not allow him to even run diagnostic. Local Volvo repairman ready to give up. He mentioned he could try and replace two O2 sensors or computer, but I would have to buy those items to try, and they may not fix the problem. Car is totally unusuable.

In previous forum Swedish Babe and Wallie recommended disconnecting the MAF sensor and starting or replacing the fuel pump relay.

I talked to the mechanic. He said
1. The MAF sensor was swapped with good used one and was not the problem.
2. The entire fuel system was checked including pump, pump relays etc and there are no problems. He drove the with a fuel pressure being monitored and when the car warmed up, it stalled with normal fuel pressure.
3. The cam position sensor checked OK but was swapped with a good used one to be sure. It was not the problem.

I have not given up but the local Volvo repairman has spent 8 hours on it and is giving up. He thinks it is significant the facory Volvo dealer’s diagnostic computer will not scan the car or scroll through the diagnostic pages at all.

The Volvo dealer mechanic told the local repairman not to bring it to him, as it is probably a lost cause and a loser. I am surprised with all the electronics, they can not help diagnose the problem.

Any additional ideas would be appreciated. The car is unusable and I am at wits end with a formly perfect car.