Three cylinder misfire

[Doc3g]

I was on my way to Home Depot and after a sharp right turn my check engine light came on and the truck started running rough. I pulled over and had hooked my reader up and it was showing a P300, P304, P305. I cleared the codes and drove another few miles and check again and now it has a 300, 303, 304, 305. I know I can swap coils, plugs, wires, etc, but I'm curious where the best place to start for a sudden 3-cylinder misfire. The truck still runs fine when you're on the gas, it just idles rough. Just replaced the alternator a few days ago if that adds anything to the equation.

 

[Doc3g]

Headed to pick up plugs and wires and a coil from stealership but wanted to post some pics to see if anyone can glean something from the condition of the plugs.

Denso plug from cylinder 1 (no misfire)

NGK plug from cylinder #3 (has a misfire)

Coil 1 on the left, coil 2 on the right

 

[brillo_76]

How many miles on the plugs and wires?

Sent from my SM-A505U using Tapatalk

 

[Doc3g]

How many miles on the plugs and wires?

Sent from my SM-A505U using Tapatalk

They are about 2 years old w/ 20k miles. They are "import direct" brand that a local mechanic put on. I picked up OEM from stealership yesterday and plan on putting them on today along with Denso plugs.

 

[Doc3g]

replaced the plugs, wires and #2 coil with OEM and all is well.