Sounds electrical to me. What's the vehicles voltage supply measure? You might want to go through the electrical system check sticky at the top of this forum list. Poor voltage to these ECU's will loose all kinds of gremlins. Barring that, I'd say, even thoough it was reported to have been replaced, your driver module may be suspect. Can you get someone with Rovacm,Testbook, etc. to look at the live data and see what the ECU is trying to command vs what the vehicle's actually doing? May help, not sure.