Here we go again,
2002 F150 5.4 185k miles
Had been running fine with an engine light on for a few months but smog calls. I had a P0171, P0174 and something else that pointed to the MAF.
I changed the MAF and cleared the code... smog passed.

1 week later all is good, go to leave work after long day and do my 1/2 second turn of the ignition and she doesn't start!!! it tried though so I held it longer, it started but was not easy. figured it got a fuel surge or something. Idle settled down.
Driving home it was running ok while moving (still a bit rougher than this morning) but would start to stumble after 10 20 seconds at a stop and at one point stalled. but it started back up. rest of the trip I put in neutral to keep idle up at lights.

anyway, I got both the 171 and 174 codes. I'm going to go out and check the MAF connection, PVC, obvious vacuum leaks etc.

Anyone have any ideas of what this may be?
My next step is 02 sensors but figured with both banks at the same time would indicate a central root cause. if there is something easier/less $ I would be willing to try that first. Any ideas?

Kindest,

 

Never mind, I opened the hood and the PCV had snapped, I was able to put it back together good enough to get to the store and replace it. should be good.

 

I'd also go first to fuel delivery on a lean code. Stopped up filter, worn pump or something. Fingers crossed you have it.