So about a week ago i got the P0301 misfire code that popped on. Following Donkey's guide on ruling out some of the problems, ive ruled out some possibilities.
1. Its not the spark plug/s. I replaced them with ngk iridiums that were gapped at .30. Ive also cleaned the coils and bolts with crc electronics cleaner.
2. Replaced the fuel filter (which I think got rid of a previous issue of mine haha) and am currently running a bottle of Seafoam through the engine now.
3. Its not the coil/coilpack. I swapped 1 and 3 and the misfire is still in the same cylinder.
4. I do not have a lightweight flywheel or crank pulley.
So the misfire is solely isolated to cylinder 1. What issues could cause the singular misfire?
Some other information. ~127,000mi on the car. Car runs on 93 pump gas here in MO (quiktrip if anyone cares). Its been tuned by a tuning shop (ET Tuning in Union MO).
It runs smoothly and without any issues. Consistent and full boost, so I dont think there is a vacuum or preturbo leak.
Whats left to check would be:
-valve clearances & compression. Leakdown/compression test on that single cylinder.
-O2 sensor possibly?
Any ideas besides that? Also, as I dont notice any irregularities while driving, is it safe to continue to daily drive with that cel on? I dont want to damage the engine.