I have a 2000 f150 v8 5.4. I have a code for cylinder 1 misfire. Also when I bought the truck from a private seller he told me the catalytic converter maybe needing replacing. For a couple weeks the truck was fine but now when driving it shakes and goes slow. I have to give it a lot of gas in order for it to stop but once I get back to slowing down even a tiny bit it starts doing it again. People say it could be the boot that goes over the spark plug on cylinder one doing it or the catalytic converter. Has any one else had this problem?

 

Mod's, can you move this to the right section for the OP.

You are likely due for new COP's (Coil on Plug). The rear-most plug on the passenger side is very susceptible to water dripping from the AC condenser causing the plug well to fill up water. This causes a misfire.

These are on Ebay.ca, but gives you an idea
http://www.ebay.ca/itm/Set-of-8-Igni...JWlzuX&vxp=mtr

Do the plugs at the same time. When you go to re-install the plugs, make sure they are torqued down correctly as they are known to spit out (I had one come out on my 2000). use Di-electric grease on the inside of the plug boots too.

The back two plugs are a pain to get at, but doable. I used to unbolt the fuel rail and lift it slightly to get better access to the COP's and plugs.

 

A muffler shop can test your cats for blockage. You have 4 of them, 2 on each side.

I'd be very leery of cheap Ebay coils.

Use Motorcraft plugs and torque them to 28 ft/lb.