Recently got this code again P0300. It is probably the 3 time I have had it in the last few years. The previous times it happened after work on the way home so I let the car sit overnight and it was fine the next day. This time it seems to be acting up a little more so I decided to try and fix it this time. Seems to really only happen after heavy rains.
What I have done so far:
Replaced PCV valve
Cleaned EGR valve
Changed and gapped new plugs to spec ( the back left and middle plug has some oil but doubt this will cause a misfire)
Cleaned MAF
Checked for vacuum leaks but couldnt find any (sometimes get small evap leak code P0442)
FPR and Crank Sensor were changed last year
OHM checked fuel injectors
Got some seafoam to try out
Knocked on Cat and didnt hear rattling.
I want to test the coil packs by doing an OHM test. Can anyone provide detailed step by step instructions how to do this? I also read it could be a bad O2 sensor but wouldnt that throw its own code? Or how can I test the O2 sensor myself? Any other ideas? The code hasn't come back yet (been 1 day) but a few times I picked it up as a pending code and one time the service light started flashing for a few seconds and went out so I am assuming the problem hasn't been fixed yet. 2000 intrigue 3.5L