juriha Posted June 23, 2013 Report Share Posted June 23, 2013 Started driving the truck daily a couple weeks ago with the nice weather...mods are in sig. Went to a shopping center, came out and left, on the way home CEL comes on. Pulled codes when I got home. PO0172 and PO0174...Fuel Banks 1 and 2 running lean... Cleaned MAF, checked all vacuum connections (replaced a vacuum cap that was dry rotted.) Reset codes, ran fine for a day then threw the same code again. AFR gauge reads between 14.5 and 15.3 during cruising, bottoms out at 10.0 whenever its in boost, and at idle in Park it will read 17-18.0 or max out AFR on lean side. A blip of the throttle will pull it down, then when it settles it maxes out again. Before this issue it would always be 14.3 during cruise, and 10.9 under boost, I've never seen AFR gauge go above 15, except when engine braking... I have read that a leaking intake gasket will cause lean conditions, but would it be all of a sudden? Motor only has 10k miles on it...highly doubt its intake gasket. Fuel pressure gauge reads 60psi constantly, so I feel like I can rule out fuel pump. At this point I am hoping maybe its just bad gas? I use the same station and pump religiously...truck has been problem free for over a year with the blower. I am looking for any kind of help to remedy this, let me know what you guys think. Quote Link to comment Share on other sites More sharing options...
70chevy03ss Posted June 24, 2013 Report Share Posted June 24, 2013 Not sure but have you tried re tighting the intake bolts?? Not sure if they got hot then cold then hot. Other then that have you changed the fuel filter?? Quote Link to comment Share on other sites More sharing options...
juriha Posted June 24, 2013 Author Report Share Posted June 24, 2013 I'll retighten them and see what happens. Fuel filter was new with blower install. Quote Link to comment Share on other sites More sharing options...
juriha Posted June 29, 2013 Author Report Share Posted June 29, 2013 Anyone know what module or sensor detects conditions to produce the codes I am getting? I thought o2 sensors threw their own codes...specific to o2 sensors... Quote Link to comment Share on other sites More sharing options...
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