possible trans problem

I have been fighting this problem for 2 years, and the problem is not the transmission itself. Had it to my mechanic and all the codes point to throttle body or MAF sensor issues, but I have replaced both of those with new. Most likely problem seems to be the Powertrain/Engine Control Module, which only dealer service will handle, as you need to 'flash' the computer to reset it to match your keys. I'm not ready to pay $800 - $1000 to get it done on this old of a vehicle. Short term solution is to shut off ignition, then restart and that resets it, but that only works until the next time you need to accelerate in traffic.