Just got done finishing up my tune up. Replaced the spark plugs in my 2004 Yukon XL Denali with ACDelco 41-985 Iridium plugs (gap at 0.040) and MSD 8.5mm wires. Not that bad of a swap- the rear passenger side was a little tight but nothing a few extensions couldn't help.
Even though I only have about 43k on the truck, decided to change them. Condition was still good, however, all the gaps were set at 0.060. Not sure if that was an old factory setting or what so it was good to get them out and set the new ones at 0.040. Truck runs slightly smoother but that could be just in my head, heck- I always think my truck drives smoother after a wash and wax!
Even though I only have about 43k on the truck, decided to change them. Condition was still good, however, all the gaps were set at 0.060. Not sure if that was an old factory setting or what so it was good to get them out and set the new ones at 0.040. Truck runs slightly smoother but that could be just in my head, heck- I always think my truck drives smoother after a wash and wax!
