Last friday I was using my truck and it was extremely damp out. I developed misfires in 5,6, and 8 accoding to my scan tool. It ran fine before then but always was a little finiky when it was damp out. Today was cold and dry when I got back to it and i still have issues with 6 and 8 misfiring. I swapped to accell coils a while back and had no issues really before related to them.

Has anyone else noticed anyting like that when damp or lost 3 cylinders? It's tough driving the truck like that....

 

motor?

if its a 5.4 then it sounds to me like you need some new cop's. moisture is getting in them which is causing the misfire. you can get a full set of 8 for 70-80 bucks or the v10 kit for just under 100 bucks that way you have 2 spares. and dont forget to put dielectric grease inside the boots.

and accel is junk.

 

Where are you guys getting sets for $80? And yes it's a 5.4. I also got the lean on bank 1 code too. I'm guessing that was due to the unburned fuel being dumped into the exhaust and trying to pass the o2 sensor.

 

Sounds like a fuel filter - Rule that out first. Don't be concerned about "lean" codes yet. Focus on the misfires.

Pressure test the rail @ the schrader.

It could be the coils, - Specially junk Acells

Fuel issues first, then coils.

Global -

http://stores.ebay.com/GLOBAL-AUTOMO...QQftidZ2QQtZkm

 

Damp weather causing misfires is almost always a COP failure.
Like in the old days before COP's or Coil Paks,
when you had a single coil, distributer and plug wires, Damp weather = misfires. Some vehicles required you to carry a can of WD-40 around to soak up the moisture. That stuff has got me going quite a few times. Definately hit Ebay for your COP purchase.

 

Well I picked up 3 new COP's locally at a premium of course so I can get it up and running again. I'll do some searching on ebay to try and grab some to keep on hand. I don't drive the truck much. The Friday when it was bad, I touched #5 and I was getting a little jolt, almost like the COP was leaking voltage.

 

Fuel filters are cheaper.

 

It wasn't the fuel filter. Swapped out the 3 COP's and it's not sending any codes.

 

I was getting constant misfires during damp weather. I kept swapping out spark plugs and the misfires would go away. Eventually, I swapped out the OEM coilpacks for D.U.I. systems 4.6L coil packs and wires. But before I did that, I made sure to silicone to upper valance to keep water from leaking onto the manifold. I'm almost certain that's what caused wet (no oil) plugs on the rear cylinders.