Engine Missing - Cylinder 4

[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.

 

[mazdadude]

Not trying to be snooty(crazy), but you might have better luck, if you try posting this question in the Protege/Protege5 area.

I am curious how a sparkplug could have it's gap compressed to zero? (either a mechanic did not check the gap on the plugs before he installed, or we have a wrong plug installed?)

These are the correct application sparkplugs right? Also you might try running the engine with the hood up, and in the DARK, to examine for any sparking. Perhaps you have a plug wire arcing to ground.

 

[flcruising]

Other tests

1) Take some carb cleaner and spray around the intake manifold (Head, EGR, Throttle Body, etc.) gasket areas while the engine is idling. Be very thorough. If you hit any spots where it idles up and smooths out, you have a leak.

2) Clean your MAF sensor with either MAF cleaner or Electronic Parts Cleaner.

3) Check all your vacuum lines for leaks. If they are crumbly, it's time to replace anyways.