I am trying to diagnose an S500 that has been sitting around for 5+ years. The engine turns on, but immediately begins idle hunting even at cold start. Applying throttle input does absolutely nothing and putting the car into drive/reverse gears will hold idle without hunting or stalling.



I am immediately suspecting ETA and MAF failures. Any other suggestions or diagnostics to look at? Can I hook up a standard OBDII reader to this car to pull codes? Does a 1996 S500 have the same blinky code reader I am accustomed to on my older CIS W124/W201 cars that I can use?

There will be a round connector under hood. You will need diagnostics with that connector.

How does it run out on the highway?

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Jim

check tb wiring sounds like the problem

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1999 w140, quit voting to old, and to old to fight, a god damned veteran