2003 Yukon SLT scanner live status problems

[zmann96]

I've had a coding issue for a few years. went away once a while back had done none and now it's back.
Codes P074 and 071 both banks lean. The truck runs good, gas mileage ( not from on board) going 75-80 mph 15.7mpg.
I plugged in my scanner and this is what I have.
MIL status Off ? temp was up to 195
TPS 5.9% no movement
RPMs 530-560
MAF .83
MAP 11.2
Timing 17.5
Bank 1 LT trim 9.4
Bank 1 ST trim 0 - +1.6
Bank 2 LT trim 25 pegged no movement
Bank 2 ST Trim 23 - 27

I've done all the leak tests smoke - air pressure - propane didn't find any.

Can you tell me what the values should be for this 5.3L NA at idle?

 

[Scottydoggs]

check your fuel pressure at the rail.

 

[zmann96]

Ok, I'll do that. Had done it a while back but I'll check again

 

[Scottydoggs]

and i found this vid with vac leaks.

 

[zmann96]

and i found this vid with vac leaks.

I don't an aftermark Air Filter. I did get some ideas from the video that I'll check but like I said I did 3 different types of air leaks. I appreciate your responses Thank you

 

[Fless]

What it tells you is that if you have unmetered air getting into the throttle body, those codes can be set. Any outside air getting in past the MAF will do that.

 

[Fless]

You could also try cleaning the MAF if you haven't done that lately.

 

[zmann96]

You could also try cleaning the MAF if you haven't done that lately.

I've done that a number of times. My MAF is frequency and my multi meter doesn't have HZ on it so I may get one to see if it's functioning properly. thanks for your response.

 

[zmann96]

This morning I went out and checked all my vacuum hoses. I then used water all around the intake manifold. I didn't find any cracks and the water test produced no air leaks. I then got my propane take and went around different parts of the engine and no noticeable raise in RPMs. One thing I thought of could I have a bad evap purge solenoid that is causing the lean codes? Anyone know how to test a purge valve. there is a plug on it but not sure what the values should be.

 

[Doubeleive]

the purge solenoid would likely throw a small vacuum leak (evap) code if it was bad.

since you are unable to find a intake leak
I would monitor the fuel pressure and a do a leak down test, if that passes then
my primary suspect would be the MAF 1st, followed by the 02 sensors 2nd