In reply to 21st Nov 2008, 17:50

21st Apr 2011, 14:06

I have exactly the same problem with my 86 420 SEL.

It has been a year with no fix.

What about the cam position sensor? One tech said they fail just like the crank position sensor i.e. from heat, and self repair after 30 minutes or so???

In reply to 21st Nov 2008, 17:50

5th Oct 2013, 03:53

I have a 1989 420 SEL. Same problem. Ignition switch was the culprit. $402... no longer a problem. My car has 251,758 miles.

MERCEDES...LET'S DRIVE.

In reply to 21st Nov 2008, 17:50

3rd Dec 2013, 00:52

Hi, I'm Larry, I own an '89 420. I corrected my high idle problem by changing the OVP regulator, the car runs great, but I have no start after it gets warm; I'm thinking electronics? I don't have a service manual, but I'm working on it. I'd like your input 714 4040184. Thanks.