alrockaz

157 days later and the truck is back. Wow, that was a journey. The last delay was waiting for Holley to release their newest product, which is a handheld tuner with the ability to unlock the ECM and TCM on these newer trucks. Before this product, you had to send your ECM to HP Tuners or Holley (and presumably others) and it was hundreds of dollars just to unlock. Programming was on top of that. There were issues updating the tuner and he spent six hours getting it unlocked and tuned, with a lot of that time on the phone with Holley. Even without the challenges it would have probably been at least a two hour process. We got one of the first couple of dozen that were produced so I'm sure there are programming bugs to work out. Heads were cleaned and rebuilt and all of that buildup from the direct injection engines is gone. Only driven it a bit so far but will drive it more today and change the oil again tomorrow just in case there are any tiny metal bits from the new parts in the engine - lifters, pushrods, camshaft, valves, valve seats. The unlock for these ECMS is eight HP credits ($400) plus shop labor when applicable, and you need to have a certain version of HP tuners, and maybe specific equipment as well. New Holley tuner https://www.holley.com/products/tuners_and_programmers/handheld_tuners/diablosport_intune_i3/parts/8225-R

68,000

With the cost and ease of replacing these, I replace mine yearly regardless of miles. A dirty cabin air filter can be a source of bacteria growth, and I really don't want to encourage that growth in my vehicles. It won't necessarily happen, but I would rather take preventative measures to make sure it doesn't happen.

I'll sell you my 2020 with an AFM delete as soon as it comes out of the shop . 3 lifters failed, damaged cam, bent pushrod and likely one damaged valve. Cam was damaged in two spots and the third lifter had damage on the roller. Did not hear lifter tick beforehand, but it's was also so hot in Phoenix that windows were never down. Putting in a Texas Speed AFM delete now, cleaning the deposits in the heads (they were bad!). Mechanic already checked bearings and journals to make sure there was not metal in the system. For the record, this truck is probably over-maintained and still had the lifter failure. High quality oil and filters, always changed at 5000 miles or earlier. Once I get it back, it should be back to being the perfect truck for me.

Like redwngr said, many of those issues are related being in 4WD. Anything related to difficulty turning, shuddering when turning, etc. are related to the 4WD (lock) issues. The "low power" isn't likely low engine power but the heavy resistance of the transfer case being locked and the front wheels struggling to turn at different speeds on dry pavement. You don't notice it on dirt as one tire is able to slip on dirt (or snow, or mud). Beyond that, it's speculation for me. Maybe it was on beforehand and you didn't notice, causing damage to the diffs or transfer case. Chunks in the diff can affect acceleration, but it's less about sluggishness and more about a lot of noise and more of a surging as pieces get caught and released. The transfer case could have had something slip and bind up. I would recommend checking/draining those fluids and looking for silvery discoloration. Your shifting issues of course sound like a classic transmission issue but I could also see how the driveline could create those symptoms. I've blown up a few diffs and transfer cases off road in another vehicle. I've seen the red transfer case fluid come out as Terminator silver before when I completely destroyed a transfer case and drove on it for a while. None of my speculation covers the parking brake light. And I'm likely hitting a worst case scenario and hopefully it's something much easier and simple. Heck, I would get under the truck and make sure everything looks good. Maybe the a driveshaft is wrapped in 20' of plastic debris, or something wound around an axle and pinched a brake line.

Shop just got it torn down yesterday. One lifter in cylinder #7 was broken, but the other lifter in the same cylinder had a failed roller that didn't roll smoothly and had flat spots, so obviously the cam is now bad. I was replacing it anyway. Additionally, there's one bent rod so there's going to be one valve that needs replacing. The book time for the project for older (2017) engines was about 21 hours; this one, the book time is 32 hours. He quoted me too low, is willing to stick to the quote, but I'll work it out with him. Since he was delayed a bit, I asked him to order parts from Texas Speed for a full DFM delete. Not sure if we're going to go with LS lifters, Morel or Comp Cams, but I asked him to work it out with Texas Speed as to which are the best bet for me. We looked at the valves in the heads to check out the carbon buildup that comes with these direct injection engines. Here's one valve, and this was middle of the road. Some were significantly worse, some were a bit better. He's going to disassemble the heads and clean it all up.

$2400 for the cam, lifters and repair from that point. Add'l for the parts cost of the timing chain and water pump. Should not be any additional labor as those parts are already removed. He's not a fan of the GM water pump or timing set, so we're going with Melling. I suspect he's cheaper by several 100 than other shops, but more importantly I trust the guy. He rebuilt the transmission in my Hummer H3 as well as a few other transmissions for friends.

I just joined this dubious club. 2020 6.2 L87 engine with 68,000 miles. Found a good shop and they'll be replacing lifters and pushrods in both banks, along with a new cam. Going to replace the water pump and timing chain while I'm at it, since the existing parts are already being removed. He'll also be disabling DFM for me.

I agree with you. I went from a 2017 6.2 to a 2020 6.2 and it feels like something is bound in the drivetrain, not allowing it to spin up as freely.

I pay for Connected Vehicle as I like the features - mostly the remote start out of range of the key fob. The wifi helps on occasion as well.

2020 LTZ

Loctite and look up the torque specs to ensure you are tightening it to spec.

Thanks Dmorris. After this thread I made a point of listening and noticed that, like you said, after short stops I do not hear the sound of the fuel pump.

My 17 with the 6.2 has the fuel pump priming when opening the driver's door.