1983 300D 260,210 miles. Anyway, last week at 260,000 miles I did an oil change, a diesel purge, and changed both fuel filters, and the car ran great. Fast forward to yesterday. I filled it up and noticed it was a tad bit more clattery than usual (or else I was just being overly anal) anyway, the car still ran great, but then about 27-28 miles into my 38 mile commute, running about 55-60 mph, I felt a very slight "loss of power/surge" feeling for a 3-4 seconds, then it went away. A couple minutes later it did it again, but ever so slightly ( I don't think a passenger would even notice it, but the driver would). I brushed it off, but it did it again on my way home, but only after running flawlessly for about 26-28 miles after a cold start. Today, it did the same thing, ran perfect for the first 25-30 miles, then a very light loss of power/surge.

When it does it there is no change in motor sound or increase/decrease in RPM like if the transmission was slipping. If you floor it, it downshifts and accelerates nicely with no miss or stumble (like a partially clogged fuel filter would cause). So, what the heck could cause this? I checked all the fluids today and they are fine, and I pulled and drained the primary (in-line) fuel filter and it was fine. I do have an injector that nails a touch at startup but it quiets down after a minute or two. I'm going to pull the banjo bolt on the back of the manifold and at the ALDA and clean them out but outside of that, I am a bit stumped. I doubt it is bad fuel as the car runs fine until about 25-30 miles, then the light, intermittent power fluctuation starts.

Many thanks for any help

Glenn

__________________
2012 Mercedes ML350 Bluetec 102K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 238K (mine)
1998 Volvo S70 T5 Turbo 211K (kids)
1994 Ford F150 4WD 246K (firewood hauler)
1983 Mercedes 300D 384K (diesel commuter)