swathdiver

GM put thermostats in the K2s and that of course raises the fluid temperature for best efficiencies save durability. The 6L80s in the GMT900s seem to require overhauls after 160K miles in general. They are made to take a lot of heat but if subjected to such, the fluid should be changed sooner. Mine has the factory external cooler and doesn't get to the minimum temp to even check the fluid level when on the highway.

The front cover and connector is like your 6.2 motor? I would say then that that engine is either not a 2009 or has been gone into and put together with various parts. Sorry to hear about the 6.2, great motors.

Do it again with ACDelco Professional. Fuel pressure should be 43.5 psi running and 50-60 psi when you put the key on. Key off after charging the rail, fuel pressure should not drop more than 5 psi per minute. A leaky injector can also bleed off fuel pressure. Do you have access to a Tech-2 or other bi-directional scan tool to run tests with?

A 2009 originally came with AFM and without VVT. There were two iron block engines the LY5 and LMG, the latter was Flex Fuel. A VVT motor has an electrical connector and access plate on the front cover over the camshaft, look at your truck's motor. The non VVT will have a plain cover. If someone deleted AFM on that 2009, you'll want to know what camshaft they used, just replacing the De-Ac lifters with standard ones without changing the camshaft will cause misfires as the lobes on the AFM cylinders are of a different height. What happened to your motor exactly?

Don't forget the sporty Buick Skyhawk either!

What year and engine? 2010-2014 Gen IV 5.3 engines have AFM and VVT. 2007-2009 Gen IV engines have AFM and do not have VVT. All Gen IV 6.0 and 6.2 have VVT but not all have AFM.

Or crossing Death Valley in the summer at GCWR.

Don't forget that some tires offer less rolling resistance than others. Same when an alignment is out too. Run some bottles of Techron through some top-tier fuel through the tank. But really, towing a sail behind you is what it is.

The best part of my BlackBear tune was what he did to the transmission. Made the truck drive completely different and much more responsive and I was pleased with it beforehand. Didn't know what I was missing!

That's good. 3.9" stroke is most you can go without compromising piston life.

Will this new 6.6 be a square motor? 4" bore x 4" stroke?

The Yukon XL comes to mind.

In 2011 a shield was placed over the oil pressure relief valve in the pan to keep oil from spraying the cylinder walls. I can't imagine that the Gen V engines do not have this feature. In the same year, AFM VLOM and lifters were vastly improved but dirty oil is AFMs greatest enemy. Gen V engines have different AFM arrangement and are much more reliable and because of their extra horsepower, make more use of cylinder deactivation for improved fuel economy. AFM Gen IV engines in a Suburban rarely see V4 mode on level ground because they just don't make enough hp per cylinder to move such a load down the road. Disabling AFM has the potential to extend the life of the lifters but they can still fail, even the standard ones fail. When the lifter guides get old and crack, the lifters rotate and wipe themselves and the cam lobe out. It is also said that this can also cause a De-Ac lifter to collapse. You Gen V, K2 drivers have a lot less to worry about then those driving GMT900s with Gen IV motors equipped with AFM.

K2s with AFM 5.3s have always been paired with the 6L80. Too much of a good thing to mess up! The 6.2 was paired with the 8-speed until 2017, then with the 10-speed from 2018 and this year thus far. The 2019 5.3 DFM motor is paired up with the 8-speed.

I doubt that the Corsa exhaust will have anything to do with it unless there's a major defect in workmanship.