I have an 03 and am having the same issue. I just did the head gasket and didnt see a ground on the injector rail, where is it located? My plugs are all gaped at 40, spec is 38 to 41. Should I make the gap closer to 38? The wires on my coil pack are om properly. Any other ideas? Idle is rough and it appears to be missing.

 

its not the gap. or the fact that the wires on your coil pack are on properly or a ground on the rail O_o . If a coil pack itself is internally shorted, then its gonna have misfires on the bank of cylinders it fires. Aron, assuming you changed all gaskets (valley pan, etc) and you have misfires on one bank, its the coil pack itself.

you guys (not you aron) really need to stop believing that just becasue you have a bank of cylinders misfires means you are gonna need a head gasket.... a coil is way more likely than a head gasket any day of the week. A little diagnosis goes a long way, stress wise and financially.

 

The earlier Disco 2 had 2 ground wires that bolted to the upper intake plenum under the spark plug wire looms.
Some techs relocated them to the rear of the injector rail.
These 2 ground points were eliminated at some point before MY 2002 so if you don't see them they're not there.
If you have them they must be connected
The coil packs on the Disco2 do NOT fire an entire bank l/s 1,3,5,7 and r/s 2,4,6,8 respectively.
A single coil pack is not your problem(Ad).
There are lots of other mechanical and electrical issues that can cause a misifire or multiple misfires.
Questions need to be asked to both of you..
Were the repairs (head gaskets) made to correct a misfire and you still have the same problem, or did the misfires happen after the repair?
Have you:
Double checked spark plug wires? (Ad)

Checked cylinder compression before or after the repair?

Checked for intake manifold leaks?

Do you have any fault codes stored Aaron?

 

I'm having this EXACT same problem on my car. Been running great no problems. Then I go off-roading and it popped on the check engine light, stumbled a bit. Since then (3 days ago), it's been driving fine 85-90% of the time, then just randomly starts misfiring badly for a few seconds, then it'll be good again. I changed plugs and wires, triple checking all the connections. Didn't seem to change a thing. Also replaced air filter as the old one was looking real rough.

The codes I get are the exact same.

P1300
p0301
p0303
p0305
p0307


EDIT: It seems to usually have a 'pending' code (what's the difference in pending and logged?) of P0134, which sometimes manifests itself in the normal logged faults. But doesn't always show up. It's bank 1 sensor 1. Is that the bank for 0301 0303 0305 0307?

 

After some more tinkerimg I noticed that the connection for the drivers precat o2 sensor was loose, and moist with water inside. Cleaned it out and dried it. Then made sure the connection was good. Everything seems fine now.

 

I had my head gaskets done because I was losing cooling quick which caused overheating. Was having trouble with misfires before repair. Still haven't fixed this problem, still looking for help if anyone has an idea.

 

What was the final resolution? I am having same problem after doing head gasket for coolant leak!

 

I am having the exact same problem after replacing head gasket due to leaking coolant (02 se7). What steps should I take to trouble shoot this??? It's frustrating

 

Ground strap.
Driver's side head to firewall.
This is a silver looking braided wire with no insulation on it.
Does not need insulation as it is a ground wire.

You may need a new coil. There are two coils.

 

is your truck still using coolant? have you preasure test the system to see if the head gaskets did correct your problem.