2005 Trailblazer LT 4.2 engine 139 476 miles Pulled and cleaned original throttle body (very dirty) and replaced gasket. Tried several technics on how to relearn program from online searches no luck. When shifting into Reverse and turning wheel the car would almost stall and using a little more fuel, but durning driving it would run ok without any drop in rpms. Thought there was a problem with the throttle body so I replace it. Took it to a dealer they completed a relearn to the ecm still having high rpms about 1000 rpms didn't matter if it was a warm or cold day when started. It would take about 5 minutes or so until it would settle down to about 700 rpms and when driving it shift kinda hard between gears but would shift ok after about 20-30 driving time. Called dealer back up and they said I could have a problem with the throttle body. Removed throttle body took back to advance auto parts and exchanged it for a GM oem throttle body and took it back to dealer for programming, they said everything is working fine. Again high rpms this time 1500 to 1700 rpm on start ups didn't matter if the weather was warm or cold it would take 5-7 minutes to settle down to 800 rpms again I ? the dealer they said I could have a ecm problem. Should I replace the ecm or try to reset ecm to manufactures default as explained in your video using a 10 watt 1-ohm resistor.
Well of course try to reset it first. But they're just doing wild guessing saying it might be the computer. If I were you, I'd try to find a guy like me in your neighborhood are really understands cars and can do by directional testing of the system. Guessing with expensive parts is not a smart move
