About a month ago, I posted looking for some help/advice with a 5 and 8 cylinder misfire.

New Magnecores, new oem spec Champions, new front o2 sensors, cleaned MAF and that's it. Doing the above got rid of the o2 codes, cylinders 5 and 8 are no longer misfiring, but now 3 and 7 are misfiring.

03 D II, 98K with SAI

I should note that the truck ran free of codes or SES lights for about 15 minutes, then the SES light flashed 3-4 times, then stayed solid for the 1-2 mile drive home.

So, as it is, I've got p303 and p307 misfiring, OBD scanner indicates a level 2 severity of misfire (new reader, little documentation)

Checked plugs and both ends of wires (coil and plug ends) they "appear" to be fine, but that's just based on a visual inspection.

In preparing to tackle the original codes and troubles, I bought new coil packs, but did not replace them. I felt somewhat apprehensive about removing the upper IM, so I did not mess with the coil packs.

I don't own any other testing equipment other than the obd scanner, but can probably borrow or buy other test tools.

As always, any advice/help is appreciated.

Matt