Ok, so this I guess is our last ditch effort! I work at a MB repair shop and I surf the forums alot looking for common things and just general questions about my car, and sometimes browse through the forums looking for stuff when we get a curve ball, well we got one now.

We have a 1997 E300 Non-Turbo Diesel in here. It normally starts and runs fine, but occasionally will fall flat on its face. When starting, RPMs will idle at 1500 but immediately drop to around 150-200 but wont die, give it some gas and it eventually comes back to a normal idle. While driving it will randomly drop in idle as well and needs to duck to the side of the road to let it recover. We have swapped in a new K40 relay for known electrical problems, and checked both fuel filters but everything is fine.

Any help??? Thanks!!

 

fuel pressure? Diesels demand a lot.Leaks common in the injection pump also can cause those issues.
Lots of diesel guys on
www.peachparts.com forum

 

About 10 minutes after I posted this we figured it out, there was air being sucked in through old O-Rings on the plastic fuel lines. Allowed the car to sputter and almost die.

Thanks for the help though!!