The service guide for my '98 Ford Club Wagon says that my spark plugs should
be replaced at 100,000 miles.
With 75,000 miles on the van now, I've got mysterious stalling problems when
approaching an intersection; i.e, when decelererating.
I strongly suspect the engine is running lean. The leanness is not
overwhelming, however. There is some pinging, while on the freeway,
especially during the warmer times of the day, that was never evident
before. The timing is OK, according to the OBDII break out.
Nevertheless, it would probably be a good idea to change the spark plugs.
After all, a few misfires, especially as low idle, might cause an engine to
stall. So I looked at my service guide, and sure enough, it says I'm early
if I only have 75K miles. But wait, there is a "severe duty schedule" that
says the plugs should be changed at 60,000 miles.
This van gets a great deal of work on short-haul trips. I have heard that
this is hard on the engine lubricant. Would it wear spark plugs
prematurely? Why? Because they're "cold" much of the time? Does "cold
combustion" age spark plugs at an accelerated rate?
I would especially appreciate any shared experiences on this matter.