I have a '99 VX. The plug wasn't loose and was covered with oil when I removed it. I replaced the old plugs with Denso IK16 and I usually use Midgrade/Premium gas.

I'm counting the cylinders as driver's side back to front: 1, 3, 5 and passenger side back to front: 2, 4, 6

I swapped out the #4 and #6 ignition coil as Ldub suggested and think his solution might be correct. The original code read P0304 - Cylinder 4 Misfire Detected. After I swapped the two ignition coils, I got 2 other codes: P0356 - Ignition coil F Primary/Secondary circuit malfunction and P0300 - Random/Multiple Cylinder Misfire Detected. I then cleared the codes and started the engine until the check engine light came on again. I read the codes again and only one showed: P0356.

If I get new ignition coils, should I go with OEM or will an aftermarket part work fine?