03 Yukon xl 1500 (vin z) stutters around 4k rpm and randomly shuts off

The guy I bought it from didn’t know either, had it 6 months he said, believe it to be an old company vehicle but not sure, it definitely doesn’t run like it’s pushing 300k

I don't think there is any wiring correlation from the radio to the flex fuel sensor, but when you cut wires on the lan bus with the battery connected it's never a good idea.
I would take the time and get a meter and check each and every fuse.

Thanks for the advice that was on the list tomorrow after work, once it shuts off it’s kind of hard to get started back

Doubeleive said:

I don't think there is any wiring correlation from the radio to the flex fuel sensor, but when you cut wires on the lan bus with the battery connected it's never a good idea.
I would take the time and get a meter and check each and every fuse.

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Update, it shut off again today I smacked the fuel tank hard and since has run fine since. Ordered new fuel pump

If you haven't been able to look at the fuel pump you may want to have a new lock ring on hand to have when you replace the pump.

Fless said:

If you haven't been able to look at the fuel pump you may want to have a new lock ring on hand to have when you replace the pump.

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Ok thank you, I’ll check into that, going to cut a hole in the floor I’m out of town working and don’t think the hotel would appreciate me dropping a tank in the parking lot also it would be quite challenging by myself

I don't have time right now to write out the whole story - but I had a similar problem with my 2003 Suburban 2500. All sorts of codes , fuel pump, cam position sensor, crank position sensor, ignition codes, engine shutting off - the whole thing.

First problem I found was that mice had gotten into the wiring directly under the fuse box in the engine compartment. I had at least 4 wires completely severed and 10 more that were showing bare copper. Spent a Sunday carefully soldering and heat shrinking the wires back together to fix that problem. That still didn't stop the codes though. I kept getting them. I had a sneaking suspicion that the ECM (engine computer) was bad , but had a number of people tell me "they don't go bad" - so I kept discounting that gut feeling.

After a couple of months of screwing with it - I finally replaced the ECM with an exchange unit - and that finally fixed the problem.

I would also add - the problem on my truck appeared to be due to heat as it would run for a short time really well when the engine compartment was cold. As soon as things heated up - that's when the trouble started.

You sound like you might have a similar problem - what with a whole bunch of different codes showing.

Just my 2 cents.........

Jsmarr123 said:

Ok thank you, I’ll check into that, going to cut a hole in the floor I’m out of town working and don’t think the hotel would appreciate me dropping a tank in the parking lot also it would be quite challenging by myself

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Dropping the tank is easy - I did it on my Suburban and it was way easier than I imagined it would be. Just make sure to somehow drain as much gas out of the tank as possible. If it was me I would not cut a hole in the floor.