Hi new to the forums.. I've swapped the computer in my 1997 tbird has the 4.6l v8. Since I've swapped the pcm in the car it runs an starts better. But when driving it wont shift into 4th gear. Nothing else wrong with the trans except the fact it may need a fluid an filter change. Shifts thru the first 3 gears like it should. Anyone have any idea why the trans wont shift into od because of the computer change. ?