92 LeSabre tranny or sensor?

My LeSabre with the 4T60E transmission started acting up, and would lack power on take off, until up to speed, then it started to rev up high when it was restarted after acting up. The next thing is it was going about 45 mph on flat road with me braking it to hold it back. Now the cruise control has never worked, and have replaced the TPS, MAF, and air sensors, am going to try the shift solenoid next. I took it and had it analyzed and was told this was probably it, but they road tested it and acknowledged a problem, but said that it did not show any codes. has anyone had any similar problem, and if so what did you find the culprit to be? Also have replaced the catalytic conv, fuel pump, fuel filter, and fuel sending unit.