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2004 4.6l f150. Running rough at idle and not much better when driving. Knocking like a diesel which I am afraid is the dreaded cam phaser or cam roller. It is throwing code P0171 lean condition on bank 1. Changed all the plugs on driver side. Checked all coils and fuel injectors on driver side. Replaced Egr. Seems like a misfire but no codes for that.
Not sure I am up for a cam issue.
Attached are the scanner readings that seem relevant. Fuel pressure on bank 1 seem low? (Probably obvious). Not sure if the fuel pressure relative to manifold looks off.
You won’t have phasers to worry about as that version of the 4.6 (in this generation truck) didn’t have them.
It does seem, if that knocking is in the valvetrain, that a valve isn’t closing for some reason and extra air is ending up in the exhaust stream and the pressure regulator is trying to compensate and lean out.
Thanks for the info on the phaser. I disconnected the catalytic converter to see if it might be an issue. Doesn’t seem to be missing as bad with the cat disconnected. For the life of me I cannnot get the cat off the truck though.
Thanks, bank 1 seems to be an issue. O2 sensor 1 on bank 1 was loose. I tightened it up still super rough at idle. So I pulled that O2 sensor completely out and drove it around. Smoothed it out a bunch and wasn’t rough. I’m thinking a clogged cat is one of my issues.
Replacing that cat seems next to impossible (for me at least). Just getting to that O2 sensor was a pain.
