Help! new to the board and with a very unstable idle!
 

Help! My parents have a 1993 300E 2.8 with a critical idle problem. After about 30 seconds of starting (or if the engine is still warm) the idle bounces anywhere between 600 to 1500 RPM while in Drive, if it is in park it fluctuates as high as 2500 RPM.

I have taken the car to a certified Mercedes and Porsche mechanic and he has said that the car needs a wiring harness that is $600 for the fix. Is this the true solution? The idle is very annoying and its pulsating up and down between my specified RPM intervals. Email me too at pors944@earthlink.net if you wish to reply to the message. You can also post a reply since i just place my email on here for a faster response. Thank you for reading and any advice you can give me...

Check out what Benzmac had to say in the following thread:

http://www.peachparts.com/shopforum/tech-help/31519-1993-300e-2-8-still-ill.html?highlight=harness

While the air mass meter is a very good possibility, if it needs a wiring harness, it needs it FIRST.