Problem with my = 2004 Chevy Colorado. 5 cylinder engine.Tune up, replaced sensors, replaced spark plugs multiple times, replaced plug cores.
Idles rough. Runs fine when accelerating.Cuts off when in reverse or moving slowly forward. No codes, check engine light does not come on.
Answer: Since you did a computer code scan and there were no codes, the first thing you should do i have the throttle bore and plate cleaned. Carbon build up will cause unstable idle and stalling, especially on this electronic throttle system. This VIDEO shows how. It is on a different engine, but the procedure is the same. Also, check for a vacuum leak.