So last night my check engine light came on and I had a friend scan the car. The result was a code showing random cyclinder misfire. I had a trusted mechanic take a look at the car. Just listening to it at idle (idle randomly raises) he thought it sounds like its running lean and thought maybe the intake manifold gasket or an injector. (stock intake manifold and gasket and injectors) After taking a ride and only having it misfire at idle he then thought maybe it was running to rich and has a problem with the egr valve or coolant temp sensor. Being the mechaical genius that I am my suggestion was the plugs. I know the first step is just pull the plugs and see what they look like but I have not had time yet. We did spray some carb clean across the intake manifold and the engine didnt suck any in so I am ruling that out for now. I was just wondering if the evo 8 is partial to a particular one of these issues. Thanks for your looking.

Mods: down pipe, cat delete, hks piping, hyperflow intercooler, licp, uicp (installed after tune), hks intake, mbc, walbro 255, bc cams springs and retainers, tuned at turbo trix august 2007.

 

how old are the plugs?
That's prob the problem.

 

Very common

https://www.evolutionm.net/forums/sh...ght=p0300+code

There are a bunch of threads on it.

 

the plugs are still the stockers but the car only has 22700 on it

 

When does the code trigger? At idle or during cruise

 

im not sure i noticed it was on when i was driving but my boost gauges blocks my view of it so it could have been on when i started it up

 

put new NGK BR7ES or BPR7ES plugs in it gapped to .026. If you have ECUFlash post up a screen shot of your timing map

 

Sorry I dont have a copy of the timing map

 

why do you recommend these sepcific plugs NGK BR7ES or BPR7ES

 

a lot of ppl uses this plugs including me, misfire is a common thing on evos

 

those are the standard copper replacement plugs that match your oem spec plugs, they are just standard plugs, not the iridium ones that came stock... fouling plugs and having the misfire code is so common... most people I know change their plugs every other or every 3rd oil change, that's why the standard plugs are recommended

 

They are like 2 bucks a piece and work great.

 

ill give them a shot and see if this fixes the problem. thanks for the help

 

Ok well the I changed the plugs today with no change. The ones I took out were fine but I changed them anyway.

The idle jumps up and down like crazy. I can't find a vaccum leak and I'm not sure what else to try.

 

anyone got any suggestions