My Disco threw a P0304 code (cylinder 4 misfire) and began running really rough. I replaced the plugs and wires with Denso Platinum TT's. Needless to say it did not fix the problem. Now it's also giving me the pending P0300 code (multiple cylinder misfire). I am assuming the coil pack is bad and plan on replacing it next but was wondering if I should do anything with the fuel injectors while I have the intake manifold off. Also, since I have a slight leak in a valve/rocker cover I will be replacing them. Any recommendations for additional servicing while I have it accessible would be appreciated...

 

Have you tried snugging up the VC bolts (12 point 8mm)?

Exam engine running under cover of darkness - looking for arcs, etc.

 

How many miles on the truck, have you replaced the plug wires with good 8 mm silicone wires if so what brand.

 

I have 124K miles. Used Denso 7mm 671-8140 Original Equipment Replacement Wires.

 

They won't hold up under the hood of your Disco, that is why most people always go with an 8 mm wire.
As for the coil, it could be going bad, I would first make sure you have a good connection at the coil.
How is the engine running, the injectors, if they are acting up would also give you a 206 code.
Might want to look at a compression test to rule out a burned or sticking valve.

 

Mike, Thanks for the info. This is my first Land Rover. I've had it about two years with no problems other than routine maintenance until now. I may go ahead and pick up a set of 8mm wires so I'm not dealing with this again in six months and was already planning on a compression test. Is the reason you recommend 8mm wires because Land Rovers produce excessive heat under the hood? Also, I am about to place an order for the new coil pack, do you have any recommendations there? The only reason I brought up the injectors is because a buddy of mine recommended I have them cleaned and I would like to take care of as much maintenance as possible while I'm in there. Thanks for the info/advice.

 

Cleaning won't help coils if they are failing.
Might want to look at British Parts of Utah for STI wires along with a set of coils.
Might want to look at my major service list posted at the top of the section, especially the front drive shaft, has it been rebuilt or replaced yet?