p0303 code wtf!

ok i have an 02 2.7 and i threw a p0303 code today. yesterday i washed the engine bay, then let it dry out. Well i started it this morning and drove it to work (20 miles) and it ran perfect. well it sat at my work all day, then when i left for the day it started fine and was driving fine for about 5 miles. Then it started stumbling and the check engine light started flashing. Well i pulled over in a parking lot and turned it off popped the hood and did a quick check and everything seemed fine. so i started it back up and it drove fine the rest of the way home. Then like an hour after being home i decided i was going to try to figure out what the hell was going on. Well now it's running like crap and the at first the check engine light started flashing then it stayed on. So i parked it and pulled out the trusty scan tool and got the p0303 code. Any idea where i should start on fixing it, i know from the code it's a cylinder 3 misfire. Maybe the plugs or coil?

 

It is difficult to repair non-repeating check engine problems. From your description of your problem, it sounds like some residual water from the engine bath shorted the wiring temporarly. That is unusal considering the hot engine from all of your driving. This could be a early warning of a problem or it could be a one time occurance.
Have you ever changed the plugs ? You may want to remove number three coil and swap it with number one coil and see if the problem reoccurs. If you pull a 303 code again, it could be a bad spark plug. If you get a 301 code, then it would be the coil failing. If nothing else occurs, it was a one time problem and ramdom. I hope this helps. Good Luck.

 

ok well i changed the spark plugs (old ones were spent) and when i pulled the coil off the third cylinder guess what i found, water. So my guess is that the rubber seal that was around that coil was bad. well i cleaned it up and blew all the water off of it and out of the spark plug hole. then i cleaned the MAF, the throttle body, and then put a bottle of sea foam in my tank, and through the vacuum line, and it's running like a champ again and it's not throwing any codes now.