SteveG

Good for you. I have been working with issues on my 5.3 since day one. GM even replaced the engine. Working on buyback now. Probably going F-250 or F-350 next. 40 year Chevrolet owner. Done with GM.

Update. Flashing CEL again last Friday at 6135 miles. Dealer won't do anything till they hear from GM corporate. I did tell them about the latest bulletin. Spoke to Corporate Customer Relation on Friday and was promised a call back tomorrow (Wednesday). And the light did its thing again this morning at ~6355 miles. I am now working this via BBB since they handle Lemon Law issues in FL related to GM. I owe them a call today. I now have zero confidence in this truck. Every squeak, every rattle, every vibration sets me on edge.

This is the factory performance intake. It is stock. There is no "return to stock" since it was delivered this way. The first service advisor I dealt with told me that the CEL was caused by the cold air intake. I informed him that it was factory and find me someone who know what GM installs on their vehicles.

Just got info via OnStar that there is a recall for vehicles with the factory performance air intake. May or may not have been properly calibrated from factory.

Heck, mine is a 5.3 and after multiple flashing CEL and P0300 codes, I got a new engine at 1600 miles. Now at almost 4,000 miles and I am about to uncross my fingers.

Update. So, last flashing CEL was at 1755 miles. Dealer did a crank relearn. They also mentioned that this is a known problem and GM is working a software update that should be available by the end of June. Something about misfire sensitivity. Anyway, I took the truck and hit the road. Anyway, truck now has just over 3600 miles. About 1000 of that was towing a 30’ foot 7000# travel trailer. No issues other than the abysmal mileage while towing. 7 to 9 mpg. But truck is running strong. JLT catch can is doing its job. Getting maybe 1/2 oz of oil in 700 miles or so. Nothing scientific. It is just good to know that I am not burning it.

Update: Still got the P0300 codes. But now they want to test the injectors and EGR valve. Apparently, that was all swapped over from the old engine.

Final update: NEW ENGINE So, engineer finally showered yesterday (was supposed to be last Friday). Did some tests with specialized equipment. Determined that the engine needs to be replaced. Something about timing teeth on crank being too thick. I have a feeling there is more than that. No word when they will have new engine. Engineer determined that catch can had no issue. I swung by dealer yesterday to help service writer remove catch can. Spent 1/2 hour fighting connection on manifold and could not get it off. Didn’t want to break anything. Will call JLT on that on. Wife is also concerned how replacement engine will affect value. May also mess with summer vacation plans that involved towing a trailer.

Mine took just about two months to get. It has been in the service dept for 2+ weeks of the nine we have owned it. Now at 1600 miles, it needs a new engine. I am a loyal GM guy but this experience has not been fun. All I will say is buyer beware.

So, they have the truck. Service writer seems to be on my side. I am test engineer by trade so I think we will be good there. Anyway, it is still the generic P0300 code. No specific cylinders. This is following 4 instances of flashing CEL, one solid CEL, all before 1100 miles. Latest was flashing CEL for about a min at 1543 miles followed by flashing to solid at 1555 miles. So, think we are on solid ground that the catch can was not an issue. Plus it was catching as much oil in 150 miles as my 496 big block with 20k catches in 600+ miles. On the plus side, GM did not immediately so no on the warranty. In fact, they are flying an engineer out to look at truck on Friday.

So, the flashing CEL is back. Had a one minute flashing CEL episode and then 10 miles later started flashing again before going solid and staying on. Still staying on this morning. Mileage also dropped a lot and then started coming back up. 2021 LT TB 5.3 Advised service advisor that I installed a JLT catch can at 1400 miles after last visit and that it seemed to be catching a lot of oil already. As soon as I came into dealership, service manager came out and told me that by installing am aftermarket part, I had caused a vacuum leak and that is what is popping codes. So, I asked him to explain the four flashing CEL occurrences and solid CEL that all happened with less than 1,100 miles on truck. NO response. I have a feeling they are going to try to void any warranty work at this point. I want to love this truck. Heck, I just want to like it at this point. I have already sunk ~$1500 in accessories into it. Always been a Chevy guy. May be time to kick GM to the curb.

High vacuum can occur when you are at light throttle or when throttle closes after accelerating.

Well, this time, the tech found three loose manifold bolts. Vacuum leak could have been the issue causing a screwed up air/fuel ratio. Tended to happen when engine was in a high vacuum condition. Fingers crossed.

So, they could not duplicate. Had generic P0300 codes. Cleared now. Done 200 miles since with no issues. Fingers crossed.

So, new owner of a Silverado crew cab with standard bed and the “new for Chevy” Multiflex tailgate. Wanted to get a cap for it but ARE is telling my dealer that the beds are different between GMC and Chevy. I can understand the diffference between the regular bed and the Carbon-Pro bed on GMC but not sure what differences there are in the regular beds. ARE does offer the cap I want in the GMC standard bed/Multi-Pro gate combo. Does anyone have information on the bed differences or info I can provide to ARE via my dealer to convince them that the GMC and Chevy beds are the same?