My car is a '95 E300D OM606 Non-Turbo Engine. Its starts, Idles, and drives flawlessly with one problem, but here is a bit of a background first. I park the car indoors on a perfectly level heated garage two floors below street level. When I start it up in the morning as I said its starts fine, but if I step on the accelerator and let go, it will stumble, and almost stall. It seemed to have been doing it randomly and that was the frustrating part. Occasionally it will never do it and sometimes it will do it consistently. When it does stumble it only does it for the first few minutes, and its fine from then on.

Its not ambient temperature related, as it will do it when its either 80F or -20F outside. Its been doing it since the summer. Its strictly time dependent in the sense that it depends on how long the car has been parked. The glow plugs are relatively new, and their resistance checks out fine so please don't send me in that direction. (It will start at -20F without a block heater)

I finally however did discover a pattern as to when it will stumble. If the fuel Tank is anywhere above the 1/2 mark it will NOT stumble, as soon as the fuel in the tank goes below the 1/2 mark level it will start stumbling in the mornings, and the stumbling will get progressively worse as the tank empties. When I fill it up again there is absolutely no stumble.

Here is a bit more info. Fuel Filter and pre-filter are OK. Tried releasing the Fuel cap prior to starting on a less than 1/2 tank, but it made no difference. I can't tell if there is air in the lines because my lines are brown, and are not clear anymore, but if there was air in them why would it only be there when the fuel tank is less than 1/2 full?

I am stumped. Any ideas.

Thanks

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]