about 2 or 3 months ago and i thought it was running properly then i ran into some emission issues so i just started from the beginning and checked everything, turned out the guy before me was running the wrong plugs, they were about 1/4" shorter then the OEM plugs...i think they were the plugs for an NA. So when i bought the OEM ones (5b-11b) i put it in the whoa. night and day difference in performance! so id take the 15 minutes it takes to check it out and just pull 1 plug and see whats in there now!