Poor/No acceleration

[mark82]

When starting out the initial acceleration is OK for about 10', then there is a very noticable, spill your coffee, decrease in acceleration, perhaps a 2/3 decrease, as if the e-brake was partially engaged. Once it gets into that sub mode nothing you do with the accel pedal makes a difference except to completely remove your foot. Sometimes if I time it correctly I can get the downshift to engage about the same time as the sub mode and it restores maybe half the acceleration (still less than full normal). Those times I cannot get the downshift it crawls away very slowly at a walking pace while traffic backs up.

Mech has set the valves, replaced injector tips, timed the IP and claims there is nothing else wrong with the motor. I suspect he is just out of ideas. He said it must be the transmission. I though perhaps some sort of torque converter problem, but the trans shop says theres nothing wrong with the trans, its the motor.

It has become hazardous to drive as this occures about 95% of the time. Also has rough idle about 50% of the time and wont keep running in gear with a/c on. You get either a/c on in neutral or in gear with a/c off, not both. I am wondering if its a bad IP or bad compression in one cyl.

Any other ideas?


(79, 240d, auto)