1994 Ford F-150 slipping transmission

When I start the truck in the morning to go to work the truck runs fine. If I stop along the way shut the truck off and start it back up the check engine light will come on and the truck shifts all over the place. This will go on for several miles and then suddenly just go back to normal. The light goes off and the truck shifts fine. The problem is that this does not happen all of the time. Sometimes it will go a day and sometimes it will go for days before this will happen again. I was told that it was the shift solenoid so I replaced it. Still same problem. There is a solenoid called a (torque converter solenoid). I am hoping that it is this particular solenoid or a sensor of some sort. Any advice as to what to check would be greatly appreciated.