Engine misfire fixed, but maybe a plug/cylinder problem?

TBrackenPR5

Member
:
2003 Mazda Protege5
I had a misfire the other week, and pulled the plugs out and cylinder 2 & 4, and the plugs were pinched down and weren't firing, they had decent amount of carbon build up, but nothing way out of the ordinary. I replaced the plugs and ignition coils and so far it has been riding just fine. Engine sounds a little odd, I am wondering if it could be the seals that are giving out and the cylinder is hitting the plugs. Any advice or thoughts??
 
but why were the plugs pinched in causing the misfire? those plugs were put in 2000 miles before this happened. Just peculiar to me, want to find the problem before something really goes wrong, ya know
here is a photo of the pinched plug, these were found in cylinder 4 and 2. what could cause this?

photo(1).webp
 
Last edited:
That is odd, your piston maybe coming apart but thats worse case
 
Last edited:
Ive only put in a k&n air filter, thats about it for any kind of modifications. It runs fine now, but thats exactly what i thought before I pulled out of my street a few weeks ago and my engine went nuts and flashed the CEL at me.
 
but does the engin sound like it is running fine now is there any new noise it is making?
 
Nope, in cold weather on start up, its sounds like a little struggle, but still smooth. no knocking or anything. Revving it, theres nothing either, sounds smooth as well. My friend is a mechanic and was trying to help me solve it, and he was baffled too because the engine sounds just fine, so he didnt think it was the piston.

could it be from accelerating when then engine is still cold? because when it happened, i shifted around 4000 instead of 3000 rpms.
 
Well you shouldn't be reving that high on a cold engine but when the coil packs went bad it could have caused it pull your plugs out and see if they look ok now
 
Yeah, Im pulling them tomorrow before i seafoam it and give it and oil change. If they seem fine, then maybe the coils just went bad before. I also bought some restore to treat the cylinders as well. Hopefully it all works :/
 
Engine might've sucked something in and blew it out the exhaust valve (lucky). Do a compression test, if it's low on those cylinders you might've lost some valve seat and/or piston ring bits. Open the oil cap with the engine running and put your hand over it, or give it a listen. Is it spewing a lot of crankcase blowby?
 
If it did do the VICS screw eating then those screws would be on the screen of the first cat, they would not have gone all the way out the exhaust. Also you would have noticed the machine gun sound before they got past the cylinder. And you'd have some odd rattling and the acceleration would be weird now too.
 

New Threads and Articles

Back