I have 05 Trailblazer LT, 4.2.
I've had rough idle and CEL on/off for a year. I changed air filter, fuel pump assembly, plugs and cleaned throttle body completely. I moved coil from #3 to #2 to determine if coil was bad if code followed swap.
The rough idle has improved but CEL just came back, 0171 and 0303. So it's not coil, plugs, air filter, throttle body, fuel pump.
I'd like advice on what to look at next. Thanks!
I've had rough idle and CEL on/off for a year. I changed air filter, fuel pump assembly, plugs and cleaned throttle body completely. I moved coil from #3 to #2 to determine if coil was bad if code followed swap.
The rough idle has improved but CEL just came back, 0171 and 0303. So it's not coil, plugs, air filter, throttle body, fuel pump.
I'd like advice on what to look at next. Thanks!