420SEL stalls when warm during braking

[jhurley]

I have a 1988 Mercedes 420SEL (body style 126) that has a very annoying problem. When the car is warm, it will stall when I brake and come to a stop, or sometimes when I just slow down. The tach will drop to 500, then will continue dropping until I stall. I can put the car in neutral and restart it, but it will happen every time I slow down if the car is warm. It is particularly noticeable when the weather is warm. I have recently had a tune up, had the injectors cleaned, fuel filter, etc. but none of these help. If I notice it and quickly hit the gas, I can often prevent it. Any ideas?

 

[Francois]

If I remember correctly when the car revs go over 900 the idling control valve is kept open a bit more to keep the car from stalling when the throttle is closed suddenly. It could be that this is not happening and that the revs just drop to quickly for the idling controller to catch up.

In this case it would propably be a good idea to borrow a idle controller and/or valve from someone and test this.

This is merely speculation on my part.