Started getting Cylinder 1 Misfire code P0301 today on my discovery 2. I redid the whole top end at 111,000 miles including head gasket, valves, ignition wires, spark plugs and all relevant gaskets. This was in 2016. The truck doesn’t get many miles and now has 145k in 2022. Im trying to figure out what could be the issue. I didn’t replace the coil pack when I did it and I’m not sure the lifespan for the plugs and wires being it’s been 6 years but only 35k miles. Any help would be appreciated.

 

Normal troubleshooting. Swap known good with #1. Plugs (#3), wires (#2), coils, injectors (#3), in that order. Do one at a time to see what changes.

 

ok yeah i was gonna check the spark plugs and swap coil wire tomorrow. I don’t have a spare spark plug that matches to replace but I could swap it with another cylinder I guess. I was also curious if I need to swap the coil wire with a specific cylinder or if it doesn’t matter.

 

As long as the wire is a similar length it won’t matter.

 

What are some recommended spark plugs these days?

 

none of them will reach as it’s cylinder 1 and all the others coil wires are shorter.

 

You ever get this sorted? I’m not getting a code, but getting many misfires on Cyl 1 according to the Nanocom.



This seems to happen only when it’s pretty warm out and the engine is at temp.

I’ve not pulled any plugs and checked anything, but the Nanocom only got one other misfire on cylinder 4. I’m thinking I’ll do plugs as a matter of course, but just wondering if you found out a resolution.