Occasional Blinking "Auto Trans" dash light

I have a 1991 Isuzu Trooper that I paid $1000 dollars for in 2008 (83K miles) and it has never left me stranded anywhere (except for the time I ran out of gas, but that was my fault). It’s the best 4WD vehicle I’ve ever driven, esp. in the snow, which is why I keep it around, plus, it’s easy to work on. My problem is that occasionally right after I start her up and drive far enough and fast enough for the automatic transmission to work its way from 1st to 2nd to 3rd gear, when I begin to come to a stop and it starts downshifting the “auto trans” light on the dash begins blinking and when I agin pull away its as if the trans is stuck in third gear i.e. mucho gas pedal/not much acceleration, which could obviously be dangerous if I’m pilling out into traffic… The problem presents itself more often in the colder months of the year, and during the summer it rarely happens at all. My “fix” has been to begin moving forward or at least rev the engine a bit and quickly turn the key from on to off and back to on again. The engine sputters but remains running and the light diappears and the tranny functions normally again. Other than this minor inconveniece, the Trooper is mechanically sound and I could probably get another 50000 miles out of it so I’d like to find the cause of the problem and fix it. Is it a relay switch or something electrical? Any help is greatly appreciated. P.S. I’ve heard you guys rag on Troopers on your show, but like I said, from the mountains and back trails of Oregon to the snow covered roads of Chicago Illinois, she’s never let me down…

The auto trans light is telling you that the computer is detecting a problem. This is likely putting it into a limp/safe mode. What you need to do is take it a local, independent transmission shop and have someone figure out what error codes are associated with this. Otherwise its just throwing darts at a board - with a blindfold on.