I was reading over in the TBSCEC board that if the upshift light comes on when the engine is cranking over that the crank sensor is bad...is this correct?
I believe the indicator is that the light comes on and stays on the entire time the engine is cranking, as opposed to coming on and going off a moment later...
i dont remember if it stayed on while cranking (lost a crank sensor about 2 weeks ago) but the upshift light came on while i was driving it, just as it lost power, it stalled about 5 seconds later and wouldnt restart.
I was doing bout 130 coming from Las Vegas in my 90 2 years ago. The light came on while I was in 4th still accelerating, shifted to 5th and went out. Seems to have fulfilled its purpose at the time. Why doesn't it work as intended during normal driving?
It sounds like what you described was the light working during normal driving. It's only supposed to come on to tell you to shift when your rpm's are getting too high...