2022 Tacoma MT experiencing lugging/stutter/stumble sensation. Solved

TLDR: faulty spark plug installed at the factory

2022 Tacoma V6 Access cab 4x4 with a factory lift kit and manual transmission. Have been experiencing a hesitation/shuddering on acceleration ever since we purchased the truck (new), usually under load or on a hill. The closest description I can come up with was it felt like the engine was lugging while accelerating from 80km/hr to 100km/hr going up any kind of incline except the RPMs stayed at or above 2500 revs the whole time, never faltering. The problem occurred at lower speeds and gears too but was reliably reproducible in the scenario described. Finally took it to the dealership after convincing the rep that we can, in fact, drive a manual transmission and reproduced the problem with the Toyota mechanic in the truck. He felt it right away and said that it was definitely a problem.

The Toyota mechanic's report described the problem as a misfire under heavy load. He scanned the truck with his equipment and found a pending fault code of P0300 'random multiple misfire counters'. No error lights ever appeared on the dash. Not sure if the mechanic had to run the diagnostics with the vehicle running in order to get the code but my suspicion is that he did have to run it and read it while the fault was happening.

When the misfire occurred he saw that it was happening on cylinder 3. He had planned to swap out the spark plug to try to move the misfire to another cylinder to narrow down the issue but as soon as he took out the spark plug he saw that it was visibly bent and the gap was way out of spec.

Mechanic test drove the truck after replacing the spark plug on cylinder 3 and did not have the issue re-occur. We have now had the truck for a week and have also noticed a marked change for the better. Truck is idling smoother and at a slightly lower RPM, has way more power, and no 'burbling' noise is coming from the exhaust any longer.

Either the spark plug was damaged during installation from the factory and our problem was a one-off or Toyota was shipped a bunch of faulty spark plugs that were never visibly inspected. The mechanic had never seen or heard of this particular issue but obviously there are many people on the internet complaining about similar symptoms to the one I've described. I'm writing this in the hopes that at least some of the issues people are experiencing can be solved with a simple spark plug replacement (covered under warranty).

See exhibit A. the faulty spark plug on the left removed by the mechanic.

 

Good to know. When I bought my last car used with 70k miles on it, it had some misfires while under load. Except that car would go into limp-mode if it got a misfire while I was pushing it too hard. I replaced all the spark plugs after that happened a few times and it fixed the misfires and made the car run much better overall.
I do feel a misfire type hesitation from time to time in my truck and I have thought about changing the plugs, but I just kinda thought "it's a brand new truck, the spark plugs should be fine."
Maybe there's a chance one or more are bent like that though. Thanks for posting.