Unlike you, my 240D is automatic.... Yeah, a bit sluggish is an understatement! It's a later model (82) so I was told the HP was a little higher, and the tranny seems to be reasonably well adjusted (I have often wanted to tweak with the adjustment knob to try to get it to shift up later, or shift down sooner, but no time to do that yet, and I prefer to "leave well enough alone"!). So I can live with it in most situations (except getting on the freeway with the AC on, for example!
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I was getting tired of having the car go up a non-highway hill sluggishly in 4th (kickdown to 3rd doesn't always automatically engage, or manually with the foot "switch"), or starting from a rolling stop in a sluggish higher gear. A thread on this forum suggested that we drive an auto a bit like a manual, shifting down to 3rd (or 2nd) whenever required, and even leaving the car in 3rd when city driving, to keep the revs up and prevent that dreaded shift to 4th and subsequent dreadful acceleration. Works for me. (still wish I had a manual though!!
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