Was going down hwy with cruise on at 70 mph and car started to sputter. Pulled off hwy and it died out. This happened a couple times, car would restart but was hard to keep running. With car idling i wiggled connector at tr6 and motor stumbled. I swapped out tr6/coil with stock module/coil in order to get home. Re-installed TR6 with new D599a coil and all is well, at least for in town driving. I'm hoping that fixed it. The coil was only 2 y.O. with about 15 k miles. Anybody else have one go bad? Just wondering if I should be changing it every year.