Originally Posted by mrjaydeeone
well I looked at the maintenance records from the previous owner. The plugs were changed by the dealer in March of 07 at 91k. They shouldn't need to be replaced yet, right?
also I was told that I should replace all the 02 sensors. 1 was replaced a few months back when I got a CEL. Should I replace the rest?
spark plugs on the WJ 4.0 or 4.7 should be changed at 30,000 miles
your at 123,200 so your a bit past 30K
decent info hear on the how to http://wjjeeps.com/service/sparkplugs.htm
and you have a inline so dont have to reach to far back
also might want to do the diff and TC fluid since it may need it. if the fluid is worn out could effect MPG as well
i just changed mine on the 4.7 last Thursday at 42K+ and they were the orignals and were over gaped and needed them. will see if it helps my MPG which is normally can be from 10-16 MPG depending on what i am doing, carrying a load or taking a long trip.
Originally Posted by violant00
yeah 25 hwy its a selec-trac went to jersey last week about a 75 mile trip and thats what it read on mileage that was also going only 60 the whole time but it's true
unless you did the math i think its a bit high.
since jeep could only get 21 MPG highway with 2WD when they tested and they try to push the limited on what they can get.