'93 c1500 5.7L 4L60e transmission (please help)

[countryss]

Hey everyone my '93 is really throwing me for a loop. When driving the truck it quick shifts 1-2-3 and goes into 3rd gear lock-up at 15mph with light/normal driving. If you WOT it holds out shifts and shifts like it should. TPS, MAP, VSS, and ECT are all within limits, test drive with scan tool hooked up the trans. is doing exactly what the computer is telling it too. Had a spare computer swapped with no change. If anyone has had/seen this problem any and all help would be greatly appreciated.

 

[countryss]

Bump_

 

[countryss]

Any help?

 

[countryss]

anyone

 

[sgtpoliteness]

If you manually shift does it work ok? Is there some kind of throttle basic setting?

 

[countryss]

no it makes no change