89 740 GL stalling

My 89 740 GL wagon stalls every once and a while .
Usually I am at a stop or coming to a stop when the engine stalls. It cranks
over strong but does not fire.
After about 5 mins the engine starts and runs no problem. The first time it
happened the car ran fine and then it stalled again about 6 months later.
This past 3 weeks it has stalled 3 times. The fuel relay has been changed
also the fuel filter.

I know intermittent problems are the hardest to troubleshoot but does anyone
have any idea where to look for the cause of the stalling.

Thanks in advance
Rob

 

A good cleaning of the throttle body and of the Idle Air Control valve
underneath it should help. While cleaning the throttle body, pay special
attention to that passage on the bottom that goes to the knurled thumbscrew
underneath and from there up to the other side of the throttle plate.

The IAC valve has to be removed for a thorough cleaning - if the hoses are
brittle be gentle until they can be replaced. The IAC valve should move
freely when shaken left and right.

Expect to use half a can of carb cleaner on the two parts... no
exaggeration.

Mike