Hey all - I've got a 2003 F150 5.4 V8 with about 145K miles. I got it 4 years ago with about 115K miles on it and, while it was in good shape when I got it, I don't have a history or maintenance.

Yesterday I went to jump in after it sat for about 4 days, and although it started immediately, it was chugging a little. I drove it anyway, and after about 20 minutes the check engine light started coming on (mainly during acceleration). Every time I made a stop and turned the engine off, it started right up again. But by the time I got home (about 45 minutes and 20 miles later), the check engine light was on.

I have a diagnostic tool, and it showed the P0305 error - Cylinder 5 Misfire. After doing some research (including here), I'm going to start with new plugs and coil packs. (I could also smell a little 'rotten egg' smell, which research said could be related to the misfire.) I found everything on Amazon for $100. I also called the dealer to see if I was heading in the right direction, and while they wouldn't guarantee it, they said it sounded right. To change the plugs, coil packs and do injector cleaning, they want $800. So I think it makes sense for me to order stuff and roll up my sleeves. While it's been a while since I've worked on vehicles, I believe I'm skilled enough to change these out.

Here are the plugs and coil packs that I am ordering if anyone has any thoughts.

Just looking for any thoughts, tips, or suggestions before I take this on this weekend?

Thanks in advance!
Todd

 

Correct plugs, but those coils are garbage. The ONLY cheap coils I'd consider would be from Araparts. Otherwise, stick with Motorcraft, Delphi, or Denso. I would change just the plugs and see how it responds. Do not use antiseize and torque the plugs to 28 ft/lb. Clean the coil boots thoroughly and use dielectric grease.

 

Thanks for the heads up! I chose those coils because they got great reviews. But I haven't ordered so I will wait. I will try plugs first and see what happens. Would it seem odd that a plug would go bad "overnight"? Thanks for the feedback!

 

Cheap Chinese knockoff coils are always a crapshoot.

 

Just a quick update. I changed the plugs out over the weekend, cleared the error code from the system, and it seem to be running good. OK, it's actually running great. I checked the gap on all of the plugs as I pulled them, and they ranged from .065 to .076. This has been on my list to do for a while, so I guess I just needed to be nudged!

 

They were likely the original plugs. I ran my OE plugs to 119k and the engine still ran great.