ddchevmech

Getting p0171 and p0174 dtcs (lean) but not finding cause, any help would be appreciated.

lakemg

Do you have a Z51? If so, check your air inlet tube between the air filter and throttle body. If it has oil in it, your oil has been overfilled and you sucked some oil into it. If that's the case, you might also need to change your air filter, clean the inside of the tube, and clean your MAF. I experienced this when I bought my car and dealer overfilled the oil on my Z51. Check engine light with lean codes were one of the symptoms along with a situation where I could rev it in neutral and the RPMs would not drop down after letting off the gas. Instead, the rpms would hover and in some cases increase to the point where I would have to kill the engine.

I cleaned the air inlet tube, MAF, and ended up having to replace the air filter which the dealer reimbursed me for.

Here are the codes that I was getting:

Patman

You might get more people viewing this thread if the title was more specific