Land Rover Repair: disco II blinking check engine light, fuel pump filter, catalytic converters

Question
Hello,
I have a 99 disco II with a flashing check engine light. I took it to my local auto mech / garage that I have alot of work done at. They said the codes read engine missfire(s).

That explains the very slow speed and chugging along the disco did the day before the light came on, then blinked. The mech said he checked: the plugs and they (all 8) were fowled out with carbon(?).

They ruled out: fuel pump/filter. the catalytic conv/O2 sensors, & the coil pack/plug wires and plugs were only 3000 miles old.

What would cause the plugs to fowl out so quickly to cause the check engine light to blink?

Thank you

Answer
I don't know why your plugs are fouled, but when the light flashes, you can't drive the vehicle.  Continuing to drive it will result in melted catalytic converters.

Some possible causes of plug fouling are:  Excess fuel pressure, ignition failure, sticking valves, failed engine temp sensor, ecu failure, incorrectly installed ignition parts, clogged catalysts.

You need to perform a variety of tests to narrow down the cause of your fouling.  There's no single answer, as you can see.