I bought a 2016 Suburban last year with 89,000 miles. At first it ran smooth 99.9% of the time and would occasionally stutter a little on acceleration, and give me a check engine light. After a few miles the light would go out. Checking the computer with a reader, the report was always the same misfire on Cylinder 8.

Now with 112,000 miles the stutter was more frequent. I decided to change the spark plugs. Bought AC Delco Iridium Plugs, and new factory wires. Watched a whole lot of YT video and all mentioned how hard the spark plug in #8 was to reach. They were not kidding. I'd say the job took me 8 hours and 4 was just cylinder 8. To reach it I had to be completely under the truck and working by feel alone. My arm is bruised and bloody. But when I finally got #8 out, it did not match. 1-7 were aftermarket NGK plugs and were in pretty good shape. #8 was AC Delco, and a whole lot worse looking. The wire also was in worse shape. Much more brittle, and had some kind of white dust not he inside. My guess is the previous owner, or some shop he took it to, tried to change all 8 but just did the easy 7.




After getting the new plugs in, (and a good wash) she runs like a champ. Accelerates with tons of smooth power, and charges up the hills.

 

Yes !

Some folks did similar for spark plug #6 on Nissan Frontier and Pathfinder VG33 engines. Some would take the hood off. I did all six on my daughter's 1998 Pathfinder, was prepared to do just 5 if I could not do #6. I ended up lying down across the engine compartment, used a flashlight and mirror, and with my left hand I could get a 5/8" spark plug socket two short extensions with a universal on the spark plug and could R&R that. All six took me about an hour, hadn't done that job before. The Internet gave me help on the extensions and universal required.

Now I have magnetic spark plug sockets in 13/16, 5/8, and 14mm universal for Subaru.