I found the following information that might be helpful in your decision making.. When you do replace your plugs I would ask for another set of those factory replacement plugs that you are currently running. Your mileage is exceptional. I wonder if the high altitude has anything to do with it. For some unknown reason, I have always gotten better mileage in high altitude, even with my Cummins diesel. I lived in New Mexico for 3 years and stayed between 5,500 - 7,000 feet for most of my driving.
“We’ve been seeing a couple of problems with cars that use these spark plugs. One problem is not being able to unscrew the plugs because they have galvanized themselves to the cylinder head. This can happen because the spark plugs have been left in the engine so long that they have become part of the head. When a spark plug is stuck it can either break off or come out very hard taking the threads in the head with it. In a case like this it is likely that the head will need to be removed and sent to a machine shop to have new threads installed. We have also seen many cases where the porcelain insulator will deteriorate and leak spark well before the 90,000 mile service interval. This usually causes an engine miss and a “Check Engine” or “Service Engine Soon” light to come on. Any time you have a “Check Engine” or “Service Engine Soon” light illuminate on an OBD2 computer system you are in for an expensive adventure. OBD2 cars include some 1995 and all 1996 and newer vehicles.
Considering these examples it would be much more cost effective to change spark plugs before they cause trouble than to wait for them to act up. We recommend never leaving spark plugs in for more than 30,000 miles on most cars.”
http://www.anokaautocare.com/sparkplug.htm
Login
Register
FAQ
Search
