How long did it sit for steve? I saw a TSB mentioning failed lifters may cause a squeak or chirp at cam speed(half the engine rpm) so maybe one bled down while it sat.

 

Ah, it was squeaking... Possibly it could be that simple? I thought it was the belt, so I changed it, and the pulleys. I also have an exhaust leak from those headers, but I think that would cause all of the cylinders to have misfire, not low compression either. I really hope it is top end.

On to your question though, I have no clue. Couldn't have been long, it's an 09, but what did the bulletin say about time? Remember he had that supercharged engine in it (which he tried to sell back for $27,000)...

 

pull the heads and put lifters in it.i just did one last week.

 

Problem was a misfire with low compression?

 

Turns out it was a bad AFM lifter... but the truck does not have AFM according to the vin... The tech said that all of the bolts have been touched before. This means this is not the engine that originally came in the truck...

What 6.2L came with AFM?

 

None of them. They're full of it.

Just out of curiosity... did you just upload a new tune into it? When mine gets a bad upload, it does the exact same thing. It doesn't explain low compression, but meh.

 

there full of ...6.2 didn't come with afm.the lifters in 6.2's are bad about collasping also.i've did one with only 40 miles on it.

 

L99

The L99 is derived from the LS3 with reduced output but adds Active Fuel Management (formerly called Displacement on Demand), which allows it to run on only four cylinders during light load conditions. Applications:

• 2010 Chevrolet Camaro SS (Automatic Transmission)

There you go gents. This is an entirely possible occurance since the previous owner out-sourced all of his work to a company that works mostly on Camaros and Corvettes. The tech pulled the motor apart and visually saw the bad lifter by the way.
Also I have had my tune for a long time, about 90-120 days to be a little more specific. It was running really well for a long time, then one day I had some serious issues that went away. Then they came back in a much bigger fashion.

 

I promise this truck has an afm engine uder the hood. I held the seperated lifter myself. Its well known that many of the early L92s had afm lifters too btw but I dont think they had the afm lifter manifold, just a standard valley cover. This engine has both afm lifters and the afm valley manifold. I will attempt to snap pics monday if anyone still has doubts.

 

I would love to see... But "early" does not denote 2009, huh? Either way, I think I am going to buy HP Tuners, a DoD delete kit, and a VVT Truck cam, so I know what is inside there (down the road of course).