wondering about what seems like tranny slip

I have an issue with my 99 Suburban: In 3rd and OD it seems as if transmission is slipping (mostly between 1700 and 2200 rpm) but after ride with my trans. mechanic with scanner hooked up he says tranny is fine but he is baffled by a couple of other things that seem to be causing the problem. Here is what he says: "TCC comes on and off over and over 'by command' TCC slip shows 7000+ rpm slippage (impossible) yet when TCC does come on the slip seems (feels) normal under 100 rpms; also TPS is quite active-even with consistent throttle pressure on even grade." He is wondering...a bad computer or TPS maybe, although if computer is good we should be getting a code or even a "service engine" light if TPS is bad. I am also wondering a little bit about the fuel pump or filter. Can anyone help?

I have an issue with my 99 Suburban: In 3rd and OD it seems as if transmission is slipping (mostly between 1700 and 2200 rpm) but after ride with my trans. mechanic with scanner hooked up he says tranny is fine but he is baffled by a couple of other things that seem to be causing the problem. Here is what he says: "TCC comes on and off over and over 'by command' TCC slip shows 7000+ rpm slippage (impossible) yet when TCC does come on the slip seems (feels) normal under 100 rpms; also TPS is quite active-even with consistent throttle pressure on even grade." He is wondering...a bad computer or TPS maybe, although if computer is good we should be getting a code or even a "service engine" light if TPS is bad. I am also wondering a little bit about the fuel pump or filter. Can anyone help?

this is a 350 v8 engine ? the TPS can be tested by measuring the resistance of the connections then moving the throttle ..the resistance should change steady [no drop outs].........

TPS is possible as a cause ..but you should feel this TPS in the operation of the engine . normally this is at the 2000prm area.that it is worn..