Help Diagnosing Transmission Problem

[Johnjan]

Has anybody experienced this problem? The transmission on my 1998 C1500 Extended cab, 5.7 Vortec will not shift out of first when in drive. Coincidently, Antilock Brakes warning light comes on whenever the problem occurs. This began recently, and 50% of the time the trans shifts normally. Shutting off and restarting engine will typically cure the problem temporarily. Scanner says the computer has a throttle position sensor code even though MIL is not lit. Truck runs perfectly otherwise. Any suggestions?

[badhammer]

you need to look at the readings for the TPS. it shouldbe about .58 of a volt at idle and with truck off key on 4.50 Volts or higher it should also have a nice steady climb of the scale no big drops or spots where the readings go crazy. if the Tps is acting up it will cause the transmission to not shift because the trans. does not know how open the throttle is.