Suburban Diesel Stalling: AFR and Power Loss Issues

Had the exact same issue on my 2020 Chevy Tahoe diesel last winter. The symptoms matched perfectly, rough idle, power loss, and jerky acceleration. Turned out to be a faulty fuel injector causing an inconsistent fuel spray pattern, which messed up the fuel injection timing and created a rich mixture. The oxygen sensor readings were all over the place, and the engine computer couldn't properly adjust the fuel-air ratio. The diagnostic scan revealed multiple misfires. After replacing the bad injector and cleaning the throttle body, the engine ran smooth again. This isn't something to ignore, a bad injector can potentially damage your catalytic converter if left unchecked. The repair was significant but necessary. To avoid getting burned, suggest requesting the diagnostic scan results and asking them to show you the fuel pressure readings. A reputable shop should have no problem explaining their diagnosis. The symptoms you're describing are classic signs of fuel delivery issues, and given the mileage, it fits the typical failure pattern for these engines.

Thanks for sharing that experience, I went through something really similar with my Suburban. The check engine light had me worried, but sounds like we had the same injector problem. Getting ready to get it fixed, hoping the fuel injection system doesn't have any other surprises waiting. Do you remember roughly what you paid for the repair? Also, has everything been running smoothly since the fix, or did you notice any other issues with the intake manifold or throttle body later on?

Great you asked about the follow-up. After getting the injector replaced, my Suburban's been running like new. The mechanic found a faulty injection valve that was messing with the air-fuel ratio and causing that rich mixture error we discussed. Total bill came to 515 for parts and labor, money well spent considering how smoothly it's running now. The check engine light cleared up right after the fix, and I haven't seen it since. No more power loss or rough idle issues. Throttle response is crisp again, and fuel economy is back to normal. The intake manifold and throttle body were actually fine, it was purely an injector problem. If you're getting similar symptoms, definitely worth having it checked. The diagnostic scan should pick up similar error codes to what I had. These fuel injection systems are pretty reliable once fixed properly, and the spark plugs weren't affected in my case either. Quick tip, make sure they check the fuel pressure readings during diagnosis. That's how they confirmed my injector issue right away.

Finally took my Suburban in to get checked out after putting it off too long. The mass airflow sensor readings were way off, and just like you mentioned, the fuel injection system was the culprit. Got lucky, only one injector needed replacement, and the intake manifold was clean. Bill came to 495 total, bit less than yours but still significant. The mechanic walked me through the diagnostic scan results and showed me the oxygen sensor data that confirmed the rich mixture problem. Really appreciated their transparency, made me feel better about the whole repair. Been driving it for a few days now and what a difference! No more stalling, smooth acceleration, and that annoying check engine light is finally off. Learned my lesson about not waiting so long next time something feels off. Thanks again for helping me figure out what I was dealing with.