I have a 1989 300E Euro with a five speed. I tore my knee up, and was unable drove a stick for about 7 weeks. When I got back in it, it would start and run fine for a mile or two. Then, when the temp gauge is reading about 80, if I let the car idle, it will start running real rough, and eventually stall. If I can drive it past that point, or if I can keep it reved to 2500 or so, it warms up further, and will idle fine.

If it does stall, it won't start, and the engine bucks when you try. After sitting for 15-20 mins, it will start and run fine.

Any ideas? I'm getting real sick of this.

Seem like the same problem as I had.

Found out, after much drama that it was the Head temp COOLANT sensor (not temp gauge), located on the passenger side of Cylinder head, the rear most item, below the rocker cover, with 2 push on connectors.

To test, pull, carefully, the 2 leads off the sender leads (Brass and usually green with 2 ceramic posts), and put an ohm meter into each post. if NO resistance, somewhere from 400 - 1.2K ohms, usually, then this is your problem.

Not easy to get to, needed to 'chisel a corner on the brass to get it in. To get it out use an open ended spanner, 21mm on its head to remove, a seal ring will be attached.

Also check your distributor cap and rotor button, for Carbon build up, and intermittent firing.!

Thanks, I'll give that a try. I think the cap and wires were replaced about a year or so ago, after the car sat for a year while I tried to find a transmission for it.

Also, change fuel filters if it's time to, replace the overvoltage protection relay if you don't know it's history, and check the condition of the brushes of the voltage regulator. Run a bottle of injector cleaner with the next tank of gas.

My mechanic seems to have found the problem. Bad distributor cap, and worn plugs. I don't see why it would be an intermittent problem, but it seems to have fixed it. Accelerator cable was also about to come apart as well. So nice to get back into this after weeks in my 300D non turbo.

As the engine warms from cold, if there are cracks in the distributor cap these expand as the cap gets warmer and breakdown - misfire.