Had a misfire starting yesterday CEL came on. Took it to autozone ran a P0304 code (misfire cylinder #4). So I changed the plug and all the others while I was at it. Passenger side plugs all had oil on them around the threads and inside the plug wall, the drivers side were all bone dry. Truck is still misfiring any thoughts? Truck is a 4.6 manual 4x4 with coil pack and plus wires that go over the plug and not individual coil on pack.

 

Most likely, you also need a set of plug wires.

Plug wire boots that have soaked in oil usually don't work well after that.

 

The 97 and 98 4.6 are known to have coolant leaks at the heater hose where it connects to the tube that extends up from the intake manifold. It is common for this leak to allow coolant to drip down onto #4 sparkplug boot and well. The coolant can also migrate to the other sparkplug wells and causing misfires. Sometimes it appears to be oil but most likely its coolant. As SHO89 said you may have to remove the plugs and clean or replace and clean the boots and plug wells of the coolant. Replace the heater hose clamp at the tube to stop the leaking and install two clamps if you can.

 

Yes excellent suggestions make sure that #3 and #4 plug boots are dry and you have no leaks above the #4 plug well at the heater hose. I am on my second and 1/2 set of plug wires now and if yours haven't been replaced than you might consider it. FWIW I had one of my coil packs fail and drop the #4 cylinder ONLY. Driving along and boom, misfire. No chug, no partial fire, just a clean, even miss.

 

Thanks, I was going back and double checking all of the firing components yesterday morning, and found that the cylinder #4 injector wiring harness was loose while it was running, I clicked it in and misfiring went away almost immediately (face palm). I am going to open it back up this weekend and check the heater hose, pull the plugs and clean and replace the plug boots. Many thanks for the heads up!

 

I had similar issues on my 97 4.6. My coil pack for number 5 was bad. Not bad yo change out either. Only took me a couple of hours I decided to change the other too and broke two bolts not a couple of hours lol