Thanks for the clarification Floyd. Do you know why the coil over boots are also recommended changing?
With 100000 miles between plug changes, it is probably wise . If not dried out or cracked at 100k surely would be before the second change.Failed boots could cause a misfire or damaged coil, so it's "preventative maintenance".
I tuned my ranger up at 100,000 miles and changed the serpentine belt, tensioner pulley,idler pulley, spark plugs and wires, replaced the front brakes
, cleaned the fuel injection, replaced the manual trans fluid and differential fluid, as well as fuel and air filters. None of the above showed real signs of wear, but that's why it's called "preventative" or "scheduled" maintenance.
I will do it all again every 100,000 miles.Next time it will need rear brakes
too, with oil changes, filter changes, and fuel injection cleaning more often of course.
With the exception of Tires
, I consider maintenance other than that mentioned above to be "unscheduled".
I would say that waxing the thing every 3 mos is scheduled maintenance, but I'm just too lazy!
[Although, waxing may be as important as anything else.]