W124 E280 hunting at idle

[Olly]

Hi.

Currently driving a W124 E280. Car is a 1994, auto with 60,000 miles, and all is well, except for a little problem.

When car is warm, and in neutral only, the idle osscilates (hunts). When in neutral, the revs decay to around 500rpm, the engine 'blips' up to 1500 rpm, and the revs then decay back to 500rpm and repeats. The cycle is around every 2 to 3 seconds.

Otherwise the car behaves perfectly, and never happens when stood still in gear at the lights.

Any ideas?

 

[tom7035]

Could be a mucky throttle body - see posts already on this thread; http://forums.mercedesclub.org.uk/showthread.php?t=14244

 

[malcolm E53 AMG]

I remember in my 124 days reading about the tickover being regulated on autos by the fuel pump relay/ECU. This is to stop the engine stalling when suddenly put under load by selecting drive. Just a thought since you say when auto is engaged there isn't a problem. It may be worth checking this out after all the more obvious checks have been done.

 

[Olly]

Problem solved: a replacement Maff sensor now fitted. Car now running 100% again.