Hey all. First off, this is me eating my humble pie. I've done a lot of fun and crazy things with cars over the years without ever making a forum post. Lots of searching and reading and winging it has gotten me where I needed to go. But this whole tuning thing... It's got a steep learning curve on it.
Background:
I bought an '02 Silverado 6.0/4l80e 2wd a few years back. It was abused but I brought it back around. It ran great! I stole that drivetrain for my 1990 Suburban and the truck got what I had laying around, a good (better shape than the 6.0) 4.8 from a 2005 silverado. At the same time, I converted the truck to 4wd and put it on 38" Boggers with no lift, but that's another story, probably for another forum.
When I did the engine swap, I basically changed over just the long block so there was no rewiring of plugs or sensors. I have tried several different stock 4.8 tunes from the repository and one that I know to be 100% factory from a different forum. Even trying a 6.0 tune resulted in lean fuel trims.
While logging, I was getting STFT+LTFT in the ballpark of 40% lean. Pulling a sparkplug showed that it looked a little lean, so I knew it wasn't an O2 sensor issue (I had changed one out due to stripped threads). Also, both banks had the same trims, so I'm really confident it wasn't O2's.
Around Thanksgiving I changed the intake manifold gaskets because they were reused. This helped some with the lean issue, but not a lot.
2022.11.24 - First drive after radiator swap, new working tune - 2022.11.24.hpl
Around New Year's I blocked off the EGR due to a suspected leak. Sure enough, the flex hose from the solenoid to the intake was cracked. I just took another log tonight and it looks like my leak is completely gone at low RPM (slightly negative fuel trims now). However, I'm still 10-20% lean with a bone stock 4.8 tune.
2023.01.11 - Test Drive 1.hpl
I've included my most recent log and tune. I bought GRG's layout package but half of the channels wouldn't read so most of my tables wouldn't populate. Kinda pissed about that, but I'll fix that later. I just used the autopopulated SAE channels to get fuel trim logs.
I'm running out of ideas on what to address. I need some smart people to point out the silly thing I'm missing so I can keep learning.
tl;dr
What on earth is causing my stock 4.8 tune to be so lean on a stock 4.8 engine?