P0174 - Lean Bank 2 - 2017 6.2 Denali

[ShawnQ]

Good evening, folks.

Trying to get a CEL fixed, and having issues diagnosing it. The DTC is P0174...I have searched and read a TON.

The truck is a 2017 Denali, 6.2, 125k miles.

It had the injectors and intake gaskets changed about 20k miles ago, as well as AC condenser...but not likely an issue.

It seems to run fine, but my LTFT on Bank 2 is in the +20s...
I do not have an injector fault code.
I do not notice any major intake/vac leaks with the brake cleaner test.
I do not see/notice any major exhaust leaks.

The O2 sensors seem to be even on both banks, with voltages fluctuating as I'd expect...so I don't think it's an O2.
Im leaning towards a bad injector or an intake leak. Any obvious ways to verify? I would just expect a code if an injector was dead, or horrible power, or economy. Seems to run pretty good and mileage is about normal.

I was thinking about pulling plugs first and going from there...maybe one is obviously cleaner than the other. With a LTFT reading +20, I expect a major issue...but I'm only seeing that one DTC.

Thanks in advance

 

[jaxscuby]

LTFT +20...adding a bunch of fuel..do you smell gas when its running?
you would see it in mileage..and how it is running.

a coworker's silverado had something similar..but you could smell the gas when idling.
he had a stuck injector. same code, no msfire cels..

yes pull the plugs first.

use to swap injectors around to track down misfire codes on my rice burner.

but adding fuel is due to too much air...check for pinched intake manifold gasket..

 

[Rygrego]

Look for a vacuum leak in the intake. Idle the engine and spray starting fluid around gasket surfaces and any connection in the intake tract.