Looking to the Reddit gods for help here. I just did my 100k service on a 2011 Silverado 1500 (5.3 LT) - plugs, coolant flush, transmission fluid/filter, front suspension. Truck drives noticeably better all around, feels like butter accelerating and shifting. BUT. Prior MPG was 16 and now it’s down to 12. I did use NGK Platinum plugs and reused the wires. My only thought is to put ACDelco plugs and wires in but would that make sense?
Air filter is clean. Reputable shop did the trans fluid and alignment. Will clean the MAF shortly. Oil change 3k miles ago.
I’m on a 1500 mile road trip and it’s already not that fuel efficient lol, what would you do?
The only real change was the NGK plugs. Replace 100k wires. They’ve done their job.
Replaced wires and cleaned MAF, increase of 1.5 mpg now. Still strange but that’s progress.