'97 5.4l cylinder 1 misfire

[oldpaddy]

Hello all, I dug out the expedition this morning from the blizzard we just had and now I'm misfiring on cylinder 1 (301). I wasn't pulling the code before the storm. I did find some snow in the engine compartment.
I started her up yesterday and let her idle for a while and no codes came up. I did the same today while I dug her out and no codes came up. I drove down my road (10mph) and the engine started misfiring. I could feel it and the code came up (301). I pulled over, cleared the code and restarted the engine. Idled fine and no codes. I proceeded to drive and around 30mph it started to misfire and throw the 301 code. I continued to drive to the gas station, at around 50 - 50 mph the truck felt much better, but was still misfiring, but not as bad. I added dry gas and injector cleaner, filled up and went home. At around 30mph the misfiring kicked in again and got better at 50-55mph. I got to my road, cleared the code and restarted my engine. It drove up my road fine and idled with no codes or misfires. I let it sit for a while and tried it again. At 10mph it was fine, but at around 30mph the codes and misfire starts up again. I have let it idle for a couple of hour long sittings and have driven up and down my road repeatedly without any issues (other than the original trip). Once I hit 30mph the misfiring starts up again.
I am pulling o2 sensor codes, but my cats f'd and I've been pulling codes for a couple of months. I usually erase the 02 codes when I drive and the codes tend to only pop up once a drive. All the plugs were replaced 2 months ago, but not all the packs. I believe it's an old pack on cylinder 1 (I personally didn't change the plugs or packs).
Any ideas?

Thanks for any help!

 

[stamp11127]

Swap the cop to another plug and see if the code changes to that cylinder. Also check the condition of the boot and spring.

 

[oldpaddy]

Swap the cop to another plug and see if the code changes to that cylinder. Also check the condition of the boot and spring.

Thanks I'll give it a shot tomorrow or Saturday depending on the weather and my back.
All that shoveling landed me on my back for the rest of the day.

 

[Bedrck47]

Take a good look at the boots when you pull them I had one that had a slight burn pin hole in it. For the cost of the boots I would also put two new ones on when you swap them also use some dialect grease on the coil wire

 

[oldpaddy]

Take a good look at the boots when you pull them I had one that had a slight burn pin hole in it. Foe the cost of the boots I would also put two new ones on when you swap them also use some dialect grease on the coil wire

Will do!
Thanks a lot!

 

[oldpaddy]

Morning guys, I've got a new coil pack and plug in case I need to replace them. We have more snow and wind right now. Once the snow stops flying I'll get started. One question, am I going to have to remove the Fuel rail to access cylinder 1?

 

[Bedrck47]

You shouldn't need to remove the rail But you may want to loosen it If you do just be careful that you don't disturb the injectors or the O rings

 

[oldpaddy]

You guys are the best!
Thank you so much!

 

[oldpaddy]

I pulled out the old pack and it looked like it could be original. I didn't bother testing it on another cylinder. I changed the plug and cop and now she appears to run better than she has in a long time! No misfires, codes, and she ran and idled perfectly. We have a lot of steep hills here and for the last few months I tend to lose power going up the hills. If I'm going 50 mph going up a steep hill, by the time I get to the top I'm at 40 mph. Unless I gun it, which I don't. I drive like a little old lady on ******. It takes me approx a 1/3 of a mile to get to 45. People hate me, but I'm more concerned about treating my vehicles right. Especially an 18yr old truck.
I took a test drive and I didn't appear to lose any power. But it is extremely windy out, the roads are crap and I didn't take the steepest hills.

Thanks a lot guys!!!