Re: ED 5.0 missing on petrol.
my NC was missing pretty badly just after i got it at startup and around where you say yours is doing it.
what i found was on the dizzy cap, the contact that touch's the rotor was broken, and it had huge black areas all over where it was arking to 'try' and get a spark .
anywayz new cap and button, new leads (tehy were due for replacement) and she was all good again
i will warn (scare) you though from ford spare parts (teh only place you can buy a 5 litre dizzy cap) the list price is $233.43 and the rotor button was list $24.53
thank goodness i get ford employee discount $118.18 + $13.64 seems like a much better price
btw you should run the car on petrol at a minimum of: on startup, and shutdown, and 5 kms after starting/before coming home if its possible
this will keep injectors from dying