I have discovered a temperature-related stalling problem with my Volvo s70.

I've replaced the temp sensor and the radiator thermostat thing. I've replaced the ignition coil all the way to the spark plugs. I've replaced the first O2 sensor but the second still reads zero. Fuel pump relay replaced but not the fuel filter or the fuel pump.


Car starts normally every time. How far I am able to drive during warmup before it stalls changes with ambient temperature.

When the car stalls, Check engine light goes on but no fault codes. Upshift arrow lights up briefly after the stall.

After the engine dies, ODB2 is dead/locked up and my reader is useless. For two to three minutes, starter cranks but won't start. After this time delay, it starts back up and I am able to drive as long as I want to. But, if I stop, the car cools down, then I go through this process all over again.


An added bit of info is when I replaced the first O2 sensor, the stalling would happen sooner. And, if the vehicle is moving during this event... Often, the engine would die, tachometer would swing to zero. But, something would catch and it would start back up on its own.


If this was related to the fuel system, it would be more random and not happen exactly as I've described for over a year.

Should I try a different ECM or is something more interesting going on???

Would a dead O2 #2 really cause this?

Thanks guys.