Robert,

Did this ever get resolved?

I've been having a similar problem on my '97 C230. The A/C matter has just cropped up, with airflow from the center vents cut when I accelerate and resuming when I ease off the gas. The transmission, too, has intermittently been sticking in 2nd -- almost, as you describe, like an extreme version of the upshift delay designed in for when the car is cold (except that my tranny problem almost always happens when the car is warm). So instead of my upshift delay being greatly reduced, as you describe, it has (at random times) been greatly enhanced.

Could this *also* be a vacuum problem? Anybody have an idea?
.

__________________
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-- Paul W. (The Benzadmiral)
('03 Buick Park Avenue, charcoal/cream)
Formerly:
'97 C230, smoke silver/parchment; '86 420SEL, anthracite/light grey; '84 280CE (W123), dark blue/palomino