<e36> <M3> running rich, and shimmying

["Jean F. Welter" <jfw2@xxxxxxxxxxx>]

Hi all,

ever since I replaced the chip on my '95 M3 with a JC chip (Turner
Motorsports) the car seems to be running a tad rich. I must say that it
runs a lot smoother with the chip, no more hesitation or flat spots. But
I've watched the interior of the tailpipe gradually darken from the nice
light brown color it had before the chip. Now, after a 1500 mile highway
trip, the tailpipe is flat black. This does not seem like a good sign...
Has this been the experience of others who have switched chips? 
If not, what are likely things to look for? I suppose something that was
marginal before the swap is unable to keep up, but what? Injectors?

Next problem is a weird shimmy. The car is rock solid up to about 70 mph,
then there's a mild shake which gets worse with increasing road speed.It's
definitely downstream of the clutch. It does not go away at higher speeds
like one would expect from wheel imbalance. Also, it affects the whole car,
rather than just the steering wheel. Oddly, the amplitude of the shimmy
increases (considerably) up to about 85mph, then remains constant, but at
higher speeds the frequency starts to rise instead. Quite annoying, as it
gets transmitted to all the interior bits which start to buzz, and not very
confidence-inspiring. 
Again, where to look? The rims don't seem grossly bent (at least by eye).
Should I have them checked? Any wheel shop recommendations in NE Ohio?
Drive shaft maybe?

Thanks for your input.

Jean
'95 M3
<jfw2@domain.elided>

------------------------------