My 97 S320 with 118K miles has two problems which I believe may be one in the same. First when the engine is cold and you attempt to drive at a normal acceleration it would not accelerate and loss power. If you very gradually apply gas it would accelerate but would not change into second gear unless I would ease off the gas pedal then reapply. After about 1 tenth of a mile it would accelerate normally from then on.

Second problem, driving at highway speed, if I perform a hard acceleration (gas pedal to the floor) it would down shift as expected, rpm would increase, but power would drop off and decelerate. I can gradually accelerate to any speed I desire with no problem.

The car receives all regular maintenance (including injector cleaner with oil change) and is use to commute 160 miles per day at 75 plus mph, other than those two issues it run perfectly.

Any advice?