Originally Posted by popa
Which sould be the correct gapping for the plugs for the 2000 4.0L?
I have bought a set of new plugs (NGK in Mopar box) but I have no clue about the gapping that should have (preferrably in mm).
The gap should be on a sticker under the hood. On my '02 the sticker is on the underside of the hood itself and says .035"
Namsik commented that his old plugs were never gapped because the gap is now very wide. I just changed my factory installed plugs for the first time at 75K, the gap was very wide but the center electrode was rounded, sure sign the gap had widened due to erosion of the center electrode.
Spark prefers to jump from a nice squared off and smaller diameter electrode but if you decrease the elecrtrode diameter on a standard plug it doesn't last very long. That's the advantage of platinum tips, the tip is necked down to a smaller diameter but the platinum prevents premature wear, best of both worlds. I've ran platinum plugs for over 130,000 miles and they still look good.