Welcome!

You need to start with and ELM 327 Bluetooth scantool off of Amazon and an Android phone with the Torque app. With that you can look at your 02 sensors to see if they are cycling. Look at the charts - post up the results.

1 and 8 are on different coils, so it might be just wires or just coils. Wires are a good place to start, coils usually drop cylinders in pairs per top and bottom pairs here:
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All your 02 problems are on one side - misfire problem could be the chicken or the egg. Once you can scan the 02 you can determine if they are dead or the misfire is causing them to report dead. Watch your coolant level closely, the number one cause for 02 sensor failure is drinking antifreeze due to blown head gasket.

Also, I use more parts than most (fleet of 5 currently) and I buy the cheapest available, usually RockAuto. Don't find that much difference in quality from expensive parts.

 

 

 

How many miles? THose heads have not been off in a while! Ios option is called Carwizard

 

 

Looks like you got lucky on the wires and plugs.

Check all of the plugs, Do the plugs in the misfiring cylinders look different/wet?

If so, you'll want to get a cheap usb boroscope to attach to your phone and then look into the cylinders for signs of coolant.

 

 

I'm near the Ballard Bridge on the S. side of the ship canal. Might as well do the misting with the water bottle in the dark test just to verify the veracity of the wires... lite mist from a plant type watering bottle... engine running hood open, dark outside, look for sparks when you spray.

 

The routing of those wires need to be cleaned up. It looks like one is laying on the heat tube for the SAI and they were close to getting them in the retainers attached to valve covers...but failed.

​​​​​​​ Brian.