2007 Tahoe LT 5.3 l J code engine has a multiple misfire, replaced MAP, MAF, O2 sensors, purge valve, Fuel pump. Runs good at idle, warms up to temp, tap accelerator pedal rpm goes to 2000 then creeps up to 3000 rpm and want to climb ,so I shut it off. Have also replace throttle body. All this and have same problem. Misses going down the road bad enough it tries to stall, sputters in an uphill pull, shakes bad, let off throttle and it will straighten up and go on, Replaced APP sensor only had partial throttle response. engine at reduced power, has DTC of PO 2138, now here's the kicker, I pull the plug to inspect wires, wires are all good. What I have found is, the wiring is nothing like you find in diagrams. They way this is wired , looking from bottom of connecter as it is plugged up, PPL,LT BLU TAN being center connector, next center connector going up BLK/WHT DK BLU BRN. everything I find online is different. they show from bottom up, tan, ppl, lt blu, dk blu, brn, blk/ wht.
Have I gotten the only mismatched vehicle in the country or am I missing something all together ? Other than replacing plugs where to go next ? It will sit and idle just as nice as could be.

 

Check your throttle body wiring. Your connector pinout is wrong compared to the diagram. The wires are in the wrong order, causing your throttle and misfire issues. Unplug it and see if the idle improves. You likely have a short or damaged wires in that harness. Trace the wires back from the throttle body plug to find the problem.

 

the connector in question is the APP sensor at the accelerator pedal not the throttle body. I did not have a PO 2138 u til I replaced the accelerator pedal