Stock Yukon runnin lean?

[nonnieselman]

Hey guys, im kinda confused... :shock:

workin with a bone stock 2005 Yukon 5.3 70k miles..
SES light was on so i read the codes.

P0171 "Fuel Trim System Lean Bank 1" EPA
P0174 "Fuel Trim System Lean Bank 2" EPA
P0171 "Fuel Trim System Lean Bank 1" MH
P0174 "Fuel Trim System Lean Bank 2" MH
U1500 "Inter-device Dedicated Bus" HC

B3770 "Air Flow Control 6 (A/C) Feedback Circuit" H
B0414 "Temperature Control {single or 1} (main or front) Feedback Circuit Range/Performance" H
B0229 "Recirculate Position Feedback Circuit Range/Performance" HC
B3764 "Air Flow Control 4 (blend face and floor) Feedback Circuit" H

B0429 "Temperature Control 3 (rear) Circuit Range/Performance" H
B0434 "Temperature Control 3 (rear) Feedback Circuit Range/Performance"
C0750 "Left Front Low Tire Pressure Sensor" H
C0755 "Right Front Low Tire Pressure Sensor" H


There are the codes..
So i decided to log it idling..


Lemme know what yall think or suggest something.. haha


The truck was stumbling at idle every now and again and would die on occasion.


thanks guys!! Ill be subscribed to this and be getting the notifcations on my cell phone.
So any help is appreciated greatly!!

-Jonathan

[nonnieselman]

LTFTs are in the low positive 20%s... thats not good right??
STFTs are -~2%

[GMTECH4]

check fuel psi and also check for vacuum leaks. positive fuel trims numbers indicate a lean condition

[odd boy]

After u check fuel psi go to the DVT and command AFR lower than the commanded by 20% and see if the car improves. 14.7/1.2= 12.25.

why the TPS is 8~9%?? fix that as well and make sure that the O2's are working right by using a wideband dont rely on the narrow band to judge lean condition.

[nonnieselman]

this is a DBW throttle on the SUVs.. so it doesn't have a IAC. it uses the throttle for idle.

I haven't had time to check anything on it yet cause I've been wrking out of town..

thanks for the advice guys!!