Happy Friday!

I seriously love this truck but I'm not sure it loves me back.

FACTS

Recently purchased 03' disco w/ 04' engine. est. 75K on 04 engine, very well maintained. Started to get what felt like a miss (extremely intermittent and light; first felt after a 40 mile drive when upon arrival to the destination I was waiting in my truck for 30 minutes at idle) when the truck was at idle. Noted it and ignored for that trip. Couple of weeks go by not much to talk about. Then got worse two days ago (todays date 6/3/16), but still very intermittent. Idle miss got much worse next day (Icarsoft preemptive scanner purchase came same day (hooray)) plugged the Disco in to the scanner and got the follow readings below:

Rough Road Signal Implausible
catalyst damaging misfire multiple cylinders
cylinder 6 misfire


ATTEMPTED

Removing spark plug from #6 --looked perfect -- wondered if it was not hooked in properly to the coil pack. looked for a coil pack. Thought, where is the coil pack. Realized where it was, laughed (what else can you do). Had my dad stick his fingers back there...he still loves me for some reason. Seemed like #6 was fine.

Also used the live feed from the Icarsoft scanner to read the misses. They virtually stop when at speed. Increase when at idle in gear. Decrease but are present when at idle and in park.

Coolant level = GOOD
Coolant leak = NONE
Oil = GOOD (full no water/mixing)

PLAN

????? what should I do next

 

Check for vacuum leaks, and replace the coils and plug leads.

I have the same "rough road signal implausible" code that I will be investigating eventually. I suspect a wheel sensor.

 

Swap plugs with cylinder next to 6, see if problem follows plug. Swap wire with cylinder 5 (they are about same length) to see if problem follows wire. You need to physically remove both wires from coil pack and plug and move them.

 

You guys with no SAI have it good. With my 2002 Disco, there is no "just swap plug wires". I finally just got used to pulling the plenum off and that made life much easier. Also, I broke a new Kingsborne wire inside the connector once because once it's snapped in the coil, it does not want to come out.

Anyway, my experience has been, if there is a misfire, just take the top intake off, replace the coils ($40 a pair on eBAY) and wires ($40 Kingsbornes online) and check everything out while you have it off. Clean the IAC valve, clean the MAF sensor, and check everything out.

It's really a simple job taking the plenum off and getting that stuff out of your way.

Good luck!

 

Whoops! You're right. I keep forgetting to preface my remarks with something like "In my experience..."

Life IS good without all that stuff I don't have.

 

Overland this sounds like a nice Disco. An 04 with 75k on the engine and in good shape? Nice.

With a flashing SES and misfire on only one cylinder I would immediately suspect something in that cylinder only. So, that is probably the spark plug wire, the the spark plug, or the injector. There are other causes for misfires, but those are the most likely with only one misbehaving cylinder.

The spark plug should be easy to change. You can just swap from another cylinder and see if the misfire follows. Be sure to snap a close up of the business end of the spark plug and post it here. We always like to see those.

The plug wire is a huge pain in the butt to change. But, basically, you just follow that wire to the coil behind the upper intake, get it off, and put a new one on. No big deal except it is in a very tight spot, they generally don't sell plug wires individually, and the best way to change it is to take the intake off. If I the energy correctly the 6 wire will be on the top row of the coil, so thank your lucky stars for that. Before you do that, check the wire out for any cuts or burned spots, and be sure it isn't grounding or sparking anywhere.

Changing an injector is not the worst thing. You just remove the upper intake and the fuel rail, and pop a new one in. You'll need a few tools but nothing exotic.

 

I cannot believe someone beating the thermal 'sheet' out of a vehicle by keeping it on summer probably with AC on for half an hour at idle just to be comfortable.

That is not considerate to any vehicle. Do not expect love back.

 

Down here in Texas, Ill idle 10 min tops. But anyway...I had the same issues, found my #6 wire was melted through. When I put the wire on many moons ago, I didn't push it all the way on the plug, then it just worked it self loose and rotated into a bad position.

 

Hello all! thank you for your help. I changed the #6 spark plug wire and now she purrs! After inspecting the wire my dad noticed that the portion of the wire which connected to the coil pack was missing a porcelain insulator. Once the new wire was on we were good to go!

 

Congratulations on the fix!