85 300SD, when in gear eng will not rev up ??
 

I have a 1985 300SD Turbo. The problem is that when the vehicle is in gear the engine will only rev up to about 1100 RPM. ( Not enough power when going up any incline.) When it is in park I have no problem reving the engine up to 3000 RPM. I believe the fuel is being limited somehow when in gear, but I am not sure what controls this.
Thanks for any help.

My first guess would be a clogged fuel filter. Actually, that's my only guess at the moment, unless your air filter is REALLY clogged :eek:

Sounds familiar, check out this thread.

Go to archives to gain an understanding of how engine fuels and enriches under boost. Several very common faults might cause this condition. Common one mostly repeated is blocked hose line to alda. I would still change the fuel filter if has not been done anyways and just consider it general maintenance. Lots of reading for this type of problem. :)