My car has continued to suffer lack of torque/hesitation when the ambient temp. is above 90 degrees. This has been a problem for several years now. Once the rpm's rise above 3k it goes like hell/normal. It can bog severely in city traffic. A/C has no real effect on the problem. The car is a '92 325i 135K mi. with M3 exhaust, J.C. chip, and debaffled but othwise stock airbox. My mechanic realigned the cams and improved the problem temporarily, but did not last very long. Can the timing chain stretch that badly? Has anyone else had trouble with cam timing changing?