Hello All, I have a 2000 Disco II V8

I initially had only misfires on cylinders 4 and 7. I figured it must be the ignition coil as 4 and 7 are grouped together.

I changed suspect coil, after taking out the inlet manifold etc...

It then started up OK for a few seconds, sounding good and smooth when revved. Then it started running rough and throwing multiple misfire code, misfire on 4, 6 and 7...

My power brakes also now get weak when at idle and feels like I'm trying to push a brick with my foot.

Any advice guys???

Mike King

 

Lots of questions before answers. How many miles on truck? Have the head gaskets been done? Is it overheating? How long has it been since a good tune up? Brand of Plug wires and spark plugs you are running.

If you post the problem and the answers to these questions in the Discovery section you will receive better responses.

 

Hi D2lvr,

Thanks for reply...

Disco has 85K on the clock. Head gaskets have never been done. I believe the plug wires came with the Disco, not sure but they are numbered. No overheating...

I checked the ignition spark going to all plugs using a test tool to ground. I got sparks jumping to the tool on all cylinders.

I just tested the compression on one of the misfire cylinders ( #7 ) and got no compression. I checked another cylinder that did not have a misfire message and got 150psi...

What next? Probably a new head gasket and valve job right?

Mike King

 

are you sure you didn't mix them up.

from the top, drvr to pass

1 6
7 4

 

Hey Rovin4life,

I was extremely careful when connecting the plug wires.I have the RAVE manual CD and followed the diagram in it.

What about the lack of compression?

 

are you sure you tightened down everything correctly? didn't leave stuff in the manifold for it to get sucked down.

 

With no compression on a couple of holes, I wouldn't worry about tune related issues, it is time to open up that engine and see what has failed in the valve train.