So last Tuesday I dropped off a friend and right after I checked my oil. Then I was accelerating onto the expressway. Once I reached cruising speed I let off. When I proceeded to give my car gas I knew something was not right. It sputtered and hesitated.

I got to a gas station and checked all the known potential issues... (IC Pipes, oil level, underneath for oil pouring out, or a rod protruding out of the bottom... etc,). Everything seemed in place and just fine. Granted the engine was sputtering, the exhaust reeked like fuel, and there was no knock whatsoever on the top or the bottom end. So I am thinking this is likely a spark issue (spark plug, coil pack, etc...).

So I slowly got my Evo home and let it sit until I had time to pull out the plugs. Well this morning I got out there and pulled the plugs out. The first plug I pulled was arced (see below). I used my spark plug gapper to create a gap until I get replacement plugs. I fired it up and once all the excess fuel was burned off. The car seems to idle smooth and has regained its power. I have yet to test drive and plan on taking it easy until I figure out what went wrong.

 

How many miles do you have on those plugs?

 

Standard plugs aren't up to much imo, should be changed as part of a tune

 

i believe another guy on here had a similar issue with the ceramic base dettaching from the plug. and i've heard issues with plug #1 being torn up.

 

These are the originals and I have 19k miles on my car.

 

I have experienced intercooler pipes popping many times but this was different and it turned out they were all attached. So the spark plug was the current issue that lead to the misfiring. I am just trying to figure out the cause.

 

Now I must buy new plug for it
It seems everything need to be replace on evo!

 

I wouldn't necessarily say that. Do you? Not many if any people have been complaining about these plugs. Besides plugs are very inexpensive.

 

if your original tune was with the stock intake and then you added the filter I'd guess the boost jumped up a little from less restriction.

and the one plug has no gap! that's not good, was it gapped correctly before? or did you just drop it or something when you took it out?

 

Why is there no gap on the first plug? is there a sign of something hitting the ground electrode.

 

I didn't drop any of the plugs. I saw the lack of gap immediately when I pulled it out of the cylinder. It was gapped from the factory. Pretty sure these are factory plugs unless AMS swapped them with the tune. That is possible I suppose. Either way something happened that caused this. Yeah the drop in may have changed the boost a bit. Its possible.

 

This is how the plug was when I pulled it. There is no noticable knock or anything at idle. I have yet to put a load on the engine since I have not driven it since fixing the gap. I am going to take it easy though and drive it right to AMS and have them check it out tomorrow.

 

I'm sure AMS would of discussed swapping plugs and that you would have to pay for parts/labor as well. You didn't mention the plugs are 1 colder or anything?

Did you have any problems removing the plugs? I just went Stg-1 and thought about replacing the plugs w/new ones.The car ran so darn rich from the factory. . .makes me wonder about the carbon on them. New tune & new plugs.

 

That first sparkplugs lack of gap disturbs me. If that thats cause of the misfires (which it probably is) then my question is that caused it to happen?

Could increased boost cause that? I dont think so / i dont know?

 

I am with you man. These are good plugs and the issue lies elsewhere. These are the plugs AMS used for my 2.3 stroker in my 8. These are dependable plugs. Obviously if the gap was not closed by the detonation or whatever caused this, these plugs would be fine still and this thread wouldn't have been open. Stay tuned. I am bringin her in tomorrow. I will keep the thread updated.