Do you have a link to the video it seems to be missing in that link, how did you test the fuel injectors? Special software and hardware? EDIT: Nevermind it loaded second time I went to the page. I don't like if this is the solution because that means I'll be forced to upgrade the intake manifold that I've been looking at for years.
66K now, about 58K at the time of the original post I believe. I shouldn't have said vacuum leak but something wrong with the vacuum like maybe something plugged from the catch can (I doubt it though). I seen a few posts early on that the hp fuel pump goes bad but I think those were just faulty ones from factory. I came to the same conclusion that a mechanic won't be able to find this problem and most people won't even notice it. Waiting for it to get worse but I don't have it at all now that I tuned the VE table in HP Tuners.
I think I've come to the conclusion its a vacuum leak, high pressure pump is going bad, or fuel injector is blown out (not likely since it seems to be on both banks). I decided to wait until it gets worse to figure it out since I can't do much without better tools or taking it to a shop. I always get stuck with the stupid issues with everything.
Everything I could test with the fuel injectors showed they were okay from the computer side, I can't test more without actually taking it to a shop and seeing if they are balanced properly. I did individually turn off each injector idling the truck @ ~2500 RPM and there was no difference in any of them.
That is only powertrain which I think doesn't apply to the engine unless its like a total failure. 3 yr/36,000 mi basic, 5 yr/100,000 mi powertrain. No extended warranty, I won't buy a product I feel needs one ever. I beat on it within the first warranty to make sure whatever is going to break, breaks fast and not slow outside the warranty. I've heard too many stories of "This broke about 100 miles outside my warranty and I drove it nice the whole time."
I never found out what the issue was so I modified the VE tables in HP Tuners to reduce the fuel a bit and made it upshift easier under load for right now. I figured once it gets worse it will actually trip a code or make it so I can diagnose it. I did figure out messing with the VE tables that I was already in a rich condition because I bumped the idle up to 700 which put it in the next "section", so if you are going to increase the idle keep it under 700, I think they run 700-1200 RPM rich for cold starts in the winter.
Doing a little bit of research it looks like its potentially PCV Valve or a vacuum issue somewhere. I ordered a valve and going to replace tomorrow. For $8 its worth it to swap out just to see.
Well small update, looks like something might be going on with fuel after all. My LTFT values are peaking towards negative 17-18% over time but only at idle. The little orange "squares" spiking upward are me hitting the gas. All trims start out a 0% when engine starts. LTFT takes about 15-25 minutes to hit -17%. I noticed with my tune I'm adding fuel around the RPMs I'm feeling the issue and it gets a lot better. Not sure what to think about this yet.
Well it looks like STFT and LTFT are actually almost perfect so I think I can rule out Fuel. Looks like MAP needs to be 90kPa or higher to reproduce the shutter/misfire. I'm starting to lean more and more towards torque converter.
When I unlock it, it does stop but its also moving it outside that RPM range. I originally thought it was a torque converter issue but my trans shop said it feels/sounds like the engine. I'm using HP Tuners for the controls.
oh yeah and the labor to change these plugs isn't worth it unless you have a lot of free time on your hands and like swearing. #8 cylinder (passenger back) took about 25 minutes alone to figure out how to get out. I'd like to meet the engineer that decided we didn't need that extra 1/2" there. My idle does seem to have improved but I'm OCD and no one else in the world would notice it.
2015 Silverado 5.3L LT 4WD 63,000 miles. Recently started developing a shutter / misfire under load. Happens the most around 1250-1500 RPM. Doesn't seem to have lost any power and no codes being thrown. Here's a list of things I've done: -No misfires actively being logged over 20 minute drive. -Replaced Spark Plugs -Replaced Spark Plug Wires -Replaced MAF Sensor -Inspected transmission pan - no shavings - transmission shop doesn't think its transmission - shutter happens in 2nd-6th gear when converter is forced locked. -Tripled torque converter lock up pressure and removed TCC slip -Highly concentrated amount of seafoam through gas tank (entire bottle for less than 5 gallons of fuel) -Individually turned off each fuel injector @ 2000 RPM to see if any are failing. Nothing seemed off. -Not burning any oil. -Catch can since almost new. Only thing I've noticed is running 87 Octane instead of 93 Octane makes it worse. I'm completely out of ideas here and hoping maybe someone else has run into something similar.
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