Chevrolet Repair: 1995 C1500 5.7, throttle body injection, highway speed

Question
Truck has 205,000 hiway miles, no heavy towing.  Recently started shifting late (at redline on  rpms) 1st & 2nd & 3rd.  Sounds like engine may be bogging a bit but its not apparent looking at the tach. I changed the transmission fluid and screen. (small amount of residue on magnet in bottom of pan no sign of major wear). It seemed to help a little  but still shifts late and hard from start to highway speed acceleration.  If I let up on gas pedal and get back on it I can make it shift in the normal range.  Seems strong with no sign of slippage after shift takes place. Is there a sensor that may have gone bad? Any other ideas?  

Answer
The problem sounds like your kick down cable has gone bad. There should be a cable that runs from the transmission to the linkage on the TBI(i'm assuming it is a TBI[Throttle Body Injection]) At the throttle bracket, it is the lowest cable. It should have a little plastic box and you should be able to push on the button and slide the little plastic piece in or out of the box. This will adjust your shift points, being plastic, the cable likes to slip if it gets old. Also if you have book or have access to one it should tell you how to locate and check it but usually you have to replace them once they start to slip, the one I got for my 1992 was only like 28 dollars so it's not to bad just a real pain.