P0171 P0174 Check Engine Light CEL

[andrewwynn]

Smoke test but you can also use an unlit propane torch to spray near suspect areas while watching O₂ feedback real-time. BB is a giant diaphragm so can easily be a bug vacuum leak. You can pinch off the hose to test while watching O₂ or STFT.

Also; FPR uses vacuum hose for pressure reference to intake. You said that was replaced if that's plugged can cause fuel pressure problems.

Odd to see high fuel pressure and also high positive trims.

Can also be MAF sensor reporting wrong air value. The baseline calculation based on MAF the car adjusts fuel after the fact.

The error you're getting says there is unmetered air but it's the identical affect of MAF reporting inaccurate=low quantity.