On my 07 I have been struggling with the P0171/174 bank1/2 lean faults for almost a year now. It started out after a long highway drive which is probably unrelated. I ran some fuel injection cleaner on two consecutive tanks thinking maybe I got some bad fuel. That made no difference so I have smoke tested the intake and found only a leak at the orings on the PCV. I replaced and retested to verify that leak was resolved. However the problem persists. Long term fuel trims indicate an intake system leak. I have disconnected the egr pipe and verified no smoke past the seat when the egr is closed as well. I have verified and reflashed the pcm with the latest firmware to verify it is not a mapping issue. I will try to post screenshots here showing the data but over 2500 rpm the fuel trims are near 0%. At idle they are 14% bank1 and 12% bank2 and gradually drop as rpms increase. If I manually select gears and intentionally load the engine at low engine speeds to get the throttle plate open the trims drop to 4% or so. Looking for any further advice before I take it in as it is coming up to tab renewal which requires a DEQ test. MAF tests ok as well and swapped it with a friends lr3 and the readings stay the same.
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