W123

1985 300D loss of power after 20-25 mins

My wife has been driving our 85 the 35 mile trip to work everyday and has had the same problem twice now in the last couple days. After about 25 mins of driving at 70 mph, the car would lose power like a clogged fuel filter. I drove it today and it started to do the same thing after about 30 mins of driving when I floored it up a steep hill near our house at about 55mph. The fuel filters are both fresh with a new priming pump and the air filter is clean. The loss of power is temporary. The car feels fine again after slowing down or stopping.

Chassis Model Number

W123

Forums

Body and Interior Specific Aid

300D Hard Start Hot and Sporadic Power Loss?

Hi there. First i want to thank everyone at MercedesSource for all the help to us. Thank you. I lump these two symptoms together because they seem to possibly be related. First, is the regular occurrance of hard starting only when the engine is still warm. My engine starts great when completely cold, i never have to crank more than a second. But most often when i return to my car after it has sat for up to 2 hours and is still warm , i have to crank three times usually, and sometimes 4 or 5. And then, sometimes there is a real loss of power that accompanies the car after i am started.