ok so the other nite when i started my evo 9 it seems like its running on 3 cylinders. sounds just like a wrx. but all day yesterday it ran fine now its doing it again. what could be the problem? bad spark plug? all i have done is exhaust and tune. i got 53k miles. im prob due for new plugs i bought it wil 38k all stock. please help me out thanks!

 

Probably want to at least pull the plugs and check them.

 

Yeah sounds like a plug starting to go bad. I'd go ahead and replace them all.

 

yeah gonna pull them all tonight. which ones do i get to replace sorry for sounding like a noob. what about gaps? whould i have to gap them? i got some tools and is willing to try this myself.

 

of course auto zone gave me the wrong plugs, fml.

 

the proper oem plugs will be pre gapped for IXs

 

check the plugs, even if its not the plugs, a fresh set of oem plugs wouldnt hurt. do a compression test and see

 

I never trust pre gapped plugs, Have you ever met a disguntled worker??

In the past, I have found pre gapped plugs difference of .05 between them.

 

This. Always check the gaps. The whole point is to rule out a problem with the ignition system (i.e. the spark plugs) and throwing one in with a crazy gap will not fix anything, and just cause more pain and frustration down the line when you are looking else where for the culprit. Check the gaps so you know for sure its not the plugs.



Edit: Don't worry about this telling you not to change the gap. The service manual wants you to believe they are the correct gap out of the box . Just be careful with the iridium tip when adjusting the gap. If you are still running stock boost levels the gap shown there should be correct. If you have turned the boost up a little, you might want to consider narrowing it a tad.

Good luck

 

check the plugs then maby take a look at the timing and see if all the marks line up

 

If he jumped a tooth on the timing belt he would have bigger issues to deal with. Bent valves, horrible idle and driving, etc, I don't think it would just appear in some instances and not in others.

 

Could be your spark plugs, you might as well and go replace them all. Have you noticed a excess amount of smoke or unburnt fuel coming out of your exhaust?

 

no smoke but my car always seemed like it was running rich since i got it tuned and i dont have a cat so that dont help with the smell. so i can t get plugs til this week sometime. im gonna start it up soon...i might run fine again who knows it comes a goes. i hope all i need is just plugs.

 

its still running like ****. i went to autozone and got the light checked out. 4 things wrong,
-02 sensor fault beacuse not having a cat
-cylinder 1-4 heated o2 sensor (rear) heater and control circuit low
-cylinder 2 misfire condition

probable causes are faulty fuel injector, poor electrical connection, open or short circuit condition, fuel system faulty, vacuum leak, engine mechanical condition, ingnition system faulty.

so it could be more then the plugs i guess.

 

Where in pa are you. You could bring it out and I would be willing to give you a hand diagnosing it. Try starting it and just let it idle till its up to temp, My car will missfire and carry on if you try to drive it when its cold. How recently did you have it tuned?