hi Scotty im a big fan of yours, i got a 2007 chevy tahoe, and is having rough idle, check engine is on, alot of smoke out of the back pipe, what do you think is the problem? thanks

Hey I have a bit of knowledge my self and usually a rough idle could mean some exhaust leaks or some misfiring cylinders also yiu said lots of smoke from the back pipe also sounds like the head gasket is on it way out

thanks for the info,,, i replaced all 8 spark plugs and still doimg the same...

Check engine light on means a misfiring cylinder most likely or oxygen sensor because than it means it ain’t breathing try bring it to a autozone and see what the engine light it if it’s he cylinder have them wipe it off since ya changed the spark plugs but sounds like you have the head gasket going and some exhaust leaks

thank you again, i have a code reader, and it does say misfired cylinder 4, and something about a fuel injector,,,

Fuel injectors definitely could cause rough idle try cleaning them

ooh i see, should i put one of those clean injectors in the gas? is there one that u recommend?