Engine Misfire on 4th Cylinder

[kingjaydub]

I've got an '03 Mazda Protege5. The other day I was driving and noticed the car start to miss. When I came to a stop, the car idled really rough. About 15 minutes of this and the check engine light finally came on. I scanned the code and it was P0304, meaning the 4th cylinder was missing.
I pulled the plug and the gap was completely closed... which worried me. I threw all new plugs in and it idled fine. I drove about 5-10 minutes and it started to miss again, off and on. I pulled the plug to see if the gap had been closed again and it's fine. There doesn't appear to be anything inside the cylinder.
Any clue what the problem could be? I just got this car a month ago.

 

[walkingchaos]

Is there a coilpack on 4 ? ( i can never remember) possible that the coilpack is failing.

 

[justanothermp5]

could be that there the vics butterflys came loose and got sucked into your engine
it has happened to someone before on here and thats really the only way the gap on your spark plugs could get closed like that

 

[Maxx Mazda]

...the 4th cylinder was missing.

Did you find it?

Thanks, I'll be here all week! (cabpatch)

 

[PHATBOi]

could be that there the vics butterflys came loose and got sucked into your engine
it has happened to someone before on here and thats really the only way the gap on your spark plugs could get closed like that

This is what happened to me. The butterflys broke off and got sucked up in my #4 cylinder causing the gap on the plug to close and kill the cylinder. Took me 3 months to figure it out. The raw fuel the cylinder was dumping in the cat burned a hole in the catalyst so I had to gut my cat. Had to have my whole head rebuilt. Put the car back together and it is still miss firing.

I get a ramdom missfire code and obviously the warm up catalyst below threshhold bank 1 code for the cat.

I couldn't find an intake when I put mine back together so I just removed all the butterflys and put mine back on. Could this be causing my problem?

I have a new intake, ecu, coil packs, and plugs on the way. Think this will solve my problem. It is doing the same thing kingjaydub's is and is also an 03 Protege ES.

Sorry to thread jack, but this is the first I have heard of someone else having this problem. Please help. Thanks.

 

[justanothermp5]

run a non fouler on the 2nd spark plug and that should get rid of that code, as to the missfire, could be anything from a vacuum leak to a bad plug

start with the stuff u have coming, if its still there then check for vac leaks, still after that then start looking at your MAF

 

[PHATBOi]

run a non fouler on the 2nd spark plug and that should get rid of that code, as to the missfire, could be anything from a vacuum leak to a bad plug

start with the stuff u have coming, if its still there then check for vac leaks, still after that then start looking at your MAF

So put a non fouler on the #2 spark plug? I tried the non fouler on the 2nd o2 sensor but it is a universal one and the probe doesn't fit in the non fouler right and the code came back. I was going to get one of those Magnum o2 sensor simulators. Does anyone know if they work? Thanks for the info.

BTW, I am also getting a puff of white smoke at startup. Could this have anything to do with my issues?