2007 Tahoe LT3 running rich, cannot figure out why

[FuzzyChopz]

Hello everyone! I have a 2007 Tahoe 5.3L LT3 4x4. I recently detected that my car was running lean and throwing an occasional bank 1 bank 2 lean code (P0171 and P0174). So I did a home made intake smoke test and discovered 2 leaks which have been fixed. Now from one extreme to another, I went from running lean to running rich. Although I am not throwing a rich code, using a scanner, I checked my long term fuel trim (LTFT) for both banks and they hover around -14 to -18. I have 112,000 miles, a K&N intake Kit, changed cone filter a couple months ago, changed spark plugs and wires, checked fuel pressure which is 58 while idling and holds at 55 with key in ignition, and a catch can. I've also disconnected the battery to reset the fuel trims and they are back to the usual negative numbers. On the scanner my MAF Barometer pressure appears to be normal, Coolant and Intake air temp are within 5 degrees of each other. I have also recently cleaned the throttle body and MAF with the proper cleaning sprays. The car runs fine just a slight and occasional vibration during idle. Any ideas or help is highly appreciated!

 

[FuzzyChopz]

Still working on this, any and all suggestions are welcomed...

Just checked the LTFT (closed loop at idle) after updating my Edge CTS and conducting a retune of the "Economy Tune". I was reading approximately -8.0 Bank1 and -11.0 Bank2.

 

[bwg5436]

I have a 08 Yukon that lifters stuck I'm replacing all the lifters but can't find the torque specs. All help needed.

 

[BRUTUS_T_HOG]

Add LTFT and STFT together that will tell you total trim.

 

[FuzzyChopz]

STFTs appear to fluctuate between -1 and +1. So even adding them it still seems to be running rich.

 

[BRUTUS_T_HOG]

Ok. Without knowing that we didn't know if it was actually rich or not. Unplug the MAF sensor and recheck the fuel trims. I find that the CAI setup will usually throw the MAF off.

-10% is reasonable considering the CAI, it won't set a code.

Anyways if your fuel trims trend closer to 0% wth MAF unplugged the MAF is dirty or the CAI is throwing it off.

Unplug it with the key off, then start it. Ignore fuel trim until you're in closed loop

 

[ccapehartusarmyINF.(ret)]

take of the K&N put the factory intake one and see if it fixes the problem
K&N's are notorious for throwing off the mix
i used one of those K&N filters the one that goes in the factory intake and my engine started for a sec then died i took the K&N back and replaced it with a 5 dollar STP filter and she purrred like a kitten