Lango--hate to tell ya, but Dingell didn't even HAVE an opponent this year (well, no GOP opponent, anyway; I presume there was a Libertarian or Green or whatever who grabbed a few votes).
FWIW, I agree completely with you on this issue. Michigan's auto industry is suffering from *many* factors, but the continuing refusal to embrace hybrids/higher fuel efficiency is definitely a major one.
In my own district, Nancy Skinner--a strong alternate fuels/higher-efficiency auto advocate--had the best shot at taking out Joe Knollenberg in years yesterday...unfortunately, she wasn't part of the Dem wave which overtook congress yesterday. In fact, Michigan appears to have missed out on the House cleaning completely (I'm most disappointed in the failure of Jim Marcinkowski to take out Mike Rogers--Marcinkowski is a hell of a candidate and should've had more support from TPTB, but got lost in the shuffle).
On the other hand, thank God Jennifer Granholm retained her seat as Guv; she hasn't been terribly effective, but at least she recognizes the need to diversify Michigan's vast tech/manufacturing resources into stuff other than the auto industry, and Dick "Amway" DeVos would've been a complete disaster.