97 GT please help

97 GT 3800 When im driving down the road the information center light goes off and on then if i come to a stop its like the transmission stays in overdrive and wont hardley pull. it did it the other day and i pulled over and turned it off after about 5 minutes it started fine and drove fine. Ithought it was blower restrictor since first 2 settings didnt work so i put a new 1 in. fan works fine now but dash and trans still messing up. Also i had battery and altanator checked there both fine.

maybe a bad shift solenoid?

Is it throwing any codes?