just bought an 03 disco. 120k miles for $2500. flashing engine light with p0304 engine code. grounded plug to check for spark and saw none. assuming that the wire isn't on the coil properly. have spent a few hours reading this forum to determine best way forward. 7mm wires on it now. 8mm ordered this morning. best to wait and replace all?

 

Welcome to the forum. I have been to Tybee Island a couple of times,nice place. If you are going to do wires you just as well do plugs. If you get the same results it might be the coil pack. JMO D*

 

Don't drive with a flashing SES light.

 

yeah... not driving it. got that much from reading. what are the odds of just one side of the coil pack failing? figured i'd have two misfires if it was the coil...

 

Normally the companion cylinder would misfire also if it's the coil. Not always though. It depends on what fails in it. There is a chance it's just the wire. Sometimes they burn up internally. Have you tried swapping the wire with another cylinder to see if the misfire follows?

 

haven't tried swapping... at the risk of sounding like an idiot, do i have to swap both coil and plug end?

 

No. Just swap the wire. If the misfire moves with the wire, then you know it's the wire for sure. The only thing that sucks is, it's tight back there where the coils are!
No question is stupid. Not asking would be worse!

 

swapped 04 and 06. getting misfire on both. failed to mention that brake light, abs and downhill assist (?) are also lit and now throwing a 1590.

 

I would say the wire is shot. The plug or the coil could be bad too. You could take the plug out of cyl. 4 and check it out. If it looks okay, you could try swapping that too and see if the misfire changes to only cyl. 6.
Sometimes plugs go bad and can put strain on the wire and/or the coil.

 

The ABS stuff is not related to the misfires.