04 5.4 CAI lean conditions
 

I have a 04 f150 fx4 5.4 w/ Afe Cai kit, magnaflow high flow cats,borla xr1 and Gryphon w/ custom tunes for my mods, as the only performance mods. I have been dealing with a lean condition for awhile now. Only happens off idle as FT's are close to perfect at idle, but indicate a lean condition anything above idle. This is also accompanied with what sounds like spark knock, mostly audible at 2k rpms up to 2800rpms under a ~48%-60%+ load doesn't matter what gear or speed. Truck also has lack of power at highway speeds and will throw a lean dtc, but not consistently. I have checked everything possible, fuel pressure is within Ford specs, ~ @ 40psi indicated by rail pressure sensor, FPDM has been replaced as well. no vacuum leaks have been found, fuel trims at idle do not indicate one either. Spark plugs have been replaced with motorcrafts, no misfires present. I have replaced the timing chains, tensioners, guides, phasers and camshaft followers as well due to tensioners failing. Mass airflow has been changed as well,twice with new units and cleaned many times. I have began to think that its the cold air system causing this, but don't have access to a stock intake system to test with. and wouldnt the custom tunes that were written for these mods address that issue?? I just need some more input as I'm at my wit ends here.

If you don't have any vacuum leaks and have changed out the maf the next two suspect are the forward o2 sensors and exhaust manifold leakage before the o2 sensors...

Also when's the last time the spark plugs were done?

truck has 98,000 on it , plugs were done at roughly 83,000miles, wouldn't an o2 sensor and an exhaust manifold leak be biased to one bank, unless both senors went bad at the same time?? My fuel trims are even between banks all the way through the RPM range, but indicate lean off idle. and I don't hear an exhaust leak

UPDATE: Filled the truck up with ~21gal of 91 octane and the pinging has stopped, and the fuel trims are back to near normal levels, single digits + or - mostly. does this indicate the tune needs to be looked at?? Its supposed to be an 87octane towing tune. It also does the lean ping while programmed to stock and to the 87 performance tune. These are all custom PHP tunes for my mods.

Re: 04 5.4 CAI lean conditions
 

Most likely, this happened to me. The tune was too lean. Email tunes pose that risk since its not dome by datalogging on a dyno

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