Today I have a 96 S320 with ASR and it won't rev at all. When the car is first started there is no light and there is a noise under the hood that sounds like the water pump coming through the radiator. Slight actuation of the throttle turns on the light and stops the noise. Fault codes in 5 systems for EA actuator.

Definitely an actuator. The car CAN NOT be driven at all. It will only idle (does fine idling). When I gave my first reply I interpreted that the car ran bad when trying to drive, but did drive. This car won't rev at all and won't pull the grade into the shop.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician