Mercedes Benz repair: 380SL engine stalled after release the accelerator and brake, number search results, fuel pump relay

Question
Hi whunter,

I have a 1985 Mercedes 380SL.

1. When it runs over 40mph then I need to use the brake and release the accelerator pedal. The RPM drops and the engine dies sometimes. Especially when I try to get off the freeway.

2. When I use the brake to slow down before the stop light then try to let it idle cruise to the front car. The engine will surge untill it stops fully.

I have replaced the following:
idle control module
idle control valve
water temperature sensor
fuel pump relay.

Please help and have a greate New Year. Thanks.

Chester

Answer
This sounds like a bad Brake Booster.

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1985 Mercedes Benz 380SL
Part: Brake Booster
 Note:  9" diaphragm
Spacer bushing 123 292 01 50 may be needed.     
N4000-12140 Brake Booster ATE IN STOCK $547.38