1997 transmission shift point

I had a problem come up a few days ago on my 97 transport. The transmission is shifting late. It normally shifted to 2nd at about 20 mph. Now it shifts at about 32 mph. If you let off the pedal it will shift sooner. It does this for every gear shift throught the range. I recently installed a remote car starter and the problem seemed to creep up after that. I have since removed the remote starter and the problem remains. Is it possible this caused some interference with the computer and has changed the shift points?
Any ideas?

Did you unplug the battery?? Because then your car computer is empty again and the car will have to relearn its behaviour so this can be the result and will only be temporary.
Don't worry at this time.

Tom