I have the same issue- bought a 2022 GMC Sierra 1500 AT4 on 6/11/2022. Truck wasn't running right, felt a stutter or shudder under light load. Have had a few instances of lights on dashboard going off. Took the truck to dealership on 6/20/2022 and diagnosed with a bad fuel injector on #6 cylinder. Ordered part on same day, backordered, and still waiting today 8/4/2022 and still no ETA on when the dealer will receive the part. On dealers advice I am still driving the truck but its so annoying I don't enjoy it. I have called dealerships all over the country looking for this part and found a few that have them however they were ordered for a customer, can't sell. I would love to know the reason for the backorder and a realistic time table for GM to get the parts out. Would appreciate any comments anyone has relative to this matter.