83 300sd really slow/no power

[MattW]

Hi, I checked old posts but I can't find anything about my problem.

My 300sd has become a real dog lately. When I take off the engine seems to stay at 2k rpm untill about 30mph. then the rpms start to increase. then it begin to accelerate pretty good. I noticed that I have to down shift to 3rd to even go slighty uphill and even then I only go 45mph. the rpms only go upto 3k. and to go above 50mph I have to have the pedal completely on the floor. I unhooked the kickdown switch because the car would surge and lose speed when it downshifted. It almost feels like somthing is holding the engine back.

Things I already did was change the filters(fuel/tranny/air), did a valve adjustment, checked boost(11psi), removed the alda, adjusted throttle linkage, cleaned fuel tank/screen, put in lower milage injectors that sprayed and popped right.