Hi,
My 1990Volvo 740 with 2.3 litre engine and automatic transmission sometimes stops when i am driving. This can happend if i drive normally in 80-90 km/h. This happends about once a week. When it stops, i just let i roll in Drive, and it starts again after 5-10 seconds. It does not help if i press the trottle or not. I have changed Plug-wires, but itdid not help. Any other idea?

 

Are you saying the engine cuts off, then restarts after a few seconds?

 

It could be many things.

It could be a bad massflow sensor,speed sensor,fuel pump relay,fuel pump, ETC

 

Interestingly, just got the new IPD newsletter/catalog today and it has a write-up on just this type of problem. (In the article, the cause was the fuel pump/radio supression relay. No fuel to injectors when hot.)

 

Yes the black relays are known to go bad.

The easiest way to test is to swap plugs with the cooling fan relay next to the one for the fuel pump.