Wanted to say thanks for the tip about Brisk plugs. We’ve had our 2002 4.4 Range Rover for about 3 months now. Plenty of teething problems sorted by my local indy, and then the CEL and a misfire appeared last week.
I took out all the plugs, it was fitted with bkr6equp multipoint plugs. All looked ok except for the rear plugs on either side that are suffering with oil down the plug holes. The gaskets are a job for next weekend!
I tested the primary and secondary windings on each coil. Easy with a multimeter. Followed the tip on the hella website to test the secondary windings. You have to use a battery in series to test the secondaries. https://www.hella.com/techworld/uk/Technic...coil-2886/
Odd thing was that the 8 on the car were all 0.5-0.6ohms on the primaries but only 10.2v on the secondaries. Whereas some spare used ones off eBay gave the same for the primary windings, but 11.5v for the secondary windings. I wonder if the multipoint plugs put a strain on the coils in the car, which led to them giving trouble?
Anyway a new set of Brisk DR15YS silver single point plugs fitted, gapped to 0.9mm and replaced the coils with some used ones. Just got back from a test drive, the misfire has gone and the CEL is no longer flashing. So thanks once again for the recommendations on this site.