bboy_RES

iTrader: (18)

i changed my spark plugs a couple days ago (Denso Iridium) and i my car started misfiring at WOT. i got a CEL Light and it turned out to be a code P0304 which is a Cylinder 4 misfire. i reseated all the plugs to make sure i installed them correctly and it seemed to fix the problem for the most part (misfired once or twice at WOT). my car started to misfire a lot more when i went WOT last night, but the CEL Light didnt come on. how can i tell if my plug's bad or if my injector is starting to fail? could it be caused by an exhaust leak? the hanger on my catback broke off so i have a slight exhaust leak that i still need to fix.

evo150

iTrader: (51)

what is the gap of the denso plugs? try putting the stock plugs back in and see if that fixes the problem. if it does get some new stock plugs.

bboy_RES

iTrader: (18)

the denso plugs are gapped at about .028. i wouldn't need to go a step colder with my mods would i?

dbsears

iTrader: (37)

Whats the part number for your plugs? Hopefully they are not VIII plugs. You are also not suppose to gap them. They come at the reccomended gap of .022-.024. Which means yours .028 is too much gap.

Mr. Evo IX

iTrader: (5)

Make sure the two wires and coils have good connection wtih the plugs?

Did you install aftermarket wires? or is it OEM wires? Some aftermarket wires have been known to cause problems.

Next

Check the gap, plug tight in cyl head, check wire resistance.

You can also swap the coils to see if the code changes to a different P0x

Should be an easy fix since it just occured when you were doing plugs.

Mr. Evo IX

iTrader: (5)

^ this too. Make sure the reach and heat range ar stock, or lower for higher boost. I have gapped IX's as low as .020 for higher boost.

bboy_RES

iTrader: (18)

the part number for the plugs are IKH22. i looked it up on Denso's website and those are the right plugs for the IX. i'm using the oem wires. i'm gonna fix the gap on the plugs and fix my exhaust leak and see if the problems persists.