Hello All,

About 2 weeks ago I had the plugs and wires replaced in my 2001 Discovery SE7 replaced in an attempt to get rid of multiple misfires and shaking. The new plugs and wires made the drive much smoother and stopped the shakings... for about 48 hours upon which the CEL light came back on and flashed. I ordered a code reader and it appears that I am getting codes P0306 and P0300 which are misfires in Cylinder 3 and Cylinder 6. We took the car to our very trusted mechanic and he said it could either be sticking valves or the ignition coil pack, but cant be sure. When driving the car it sort of jumps and vibrates when the CEL is flashing. Any advice/help would be great, I cant afford to just start swapping out parts hoping to get the right one. Thanks again

 

test the coil packs.

 

First, it is only misfiring on #6.
What brand of wires and plugs did you install, have you checked to see if the plug is cracked or the wire is loose at the coil? Pull the plug and tell us what it looks like, clean, black and sooty or wet?

 

I had the same problem about 6 months ago. Turned out to be a bad coil pack.

 

Cheap plug wires wont last a day on these trucks.

 

brand of plugs and wires?

a flashing CEL means stop driving, you are messing up the engine.

 

The car has Magnacore 8mm wires and Denso plugs, which I know have been highly recommended by Spike. I dont think these should be the problems.

 

not sure anyone other than he has used those plugs, and they are one of 3 brands he has switched in the past year.

Like Mike said, pull #6 and see what it looks like.

 

Actually I used Denso Iridiums and Duralast plug wires when I first bought the truck and she ran GREAT.
Then the plug wires went bad after a year (20,000 miles) and because they were under warrenty and I was laid off I returned them and went with them again, did not change the plugs though.
Then as a experiment for the forum I bought Kingsbourne plug wires and E3 spark plugs.
Did not like the plugs so I went with cheap cooper plugs and same Kingsbourne plug wires.
Came to the conclusion that it was the wires being bad, orded the Magnecors and bought AutoLite Iridium plugs and the truck runs like a raped ape and I get 16 mpg drivng back and fourth to work.
SloppyJoe went with Deno Iridiums and Magnecor plug wires, he loves them, many others have also used the Denso Iridiums and have also had great luck.
Your problem is not with the plugs or wires, like Big G said look into the coil packs.

 

so you are in agreement with my post? if I said something untrue, please let me know.