I have a 1990 Accord that has a problem with the "Sport" light that only occurs sometimes. The light has come on when I start the car (then it goes off a few minutes later), when I am driving at slow speed (again then it goes off a minute or so later) and when I am driving on the freeway (again going off a minute or so later). Every time it happens I lose 1st gear (when I am start off from a light) or I lose 4th gear and it downshifts (while I was on the freeway (pretty scary when you are going 75mph and it revs up)). This has been a problem that can happen every other day or not happen for a week or two, then it starts happening again.

Does anyone have any idea what is happening??

I did some research and removed the TCU to inspect it and it appeared OK (no brown or black spots inside the unit). Should I replace it anyway? I would hate to spend the money to replace something that wasn't broke.

I had the transmission serviced and the guy told me he couldn't get a code so he only changed the transmission fluid.

I am really frustrated with this problem because other than this problem it has been a great car (I've had it for 15 years).

ANY HELP OR IDEAS WOULD BE APPRECIATED.
THANKS!