P0300 Trouble Code - Misfire after Changing plugs/wires
Quote:
Originally Posted by
avguy
That all makes much more sense now, but one thing is still not clear. Having dried the oil out of the wells before pulling the plugs, how did the firing end of the plugs look? All of them similar, nice and dry - no gunk on the electrodes?
It's always best to systematically diagnose problems, but I tend to agree about the problem perhaps being the coil. New plugs and wires improves the electrical pathway. So the fact that the misfire improved after the new parts tends to point to either a bad coil, or else some other bad wiring up the line. If it does turn out to be a bad coil (or whatever the outcome), please post it here, and help others down the road :thumbup:
Thank you so much! All four electrodes were gunk-free, thankfully.
The plugs in wells 2 and 3 were a little toasted. They looked burned, for lack of a better word. The other two (1 and 4) were in good condition though #4 was coated with oil on the non-electrode end. Some had collected pretty far down and I didn't seem to get it all out before removing the plug. I am hoping that any oil that was left didn't drip down and causing my current misfire since the vehicle operation is better but not by much. The hesitation is still present in new gears as I did my test drive (4 blocks only) just now.
I just did the spark test on my coil, and ...no light show.
My next check is to look at the O2 sensor and the fuel filter. I'm calling a local mechanic tomorrow. I have a good recommendation for someone nearby b/c my usual mechanic is near work and almost 20 miles away.
I'll relay the full diagnostic and result as soon as the solution is found so it helps the group.