What spark plugs?

[stbb]

I have a discovery 2 V8 and need to change the spark plugs. At the moment it has iridium of that are of unknown age but i belive they last 90,000 miles ( or so they say). I have had advice from using cheap ones to special gas ones ( like the brisk ones). Last year i just put cheap ones in out piccaso and have had no problems. Anyone got any view on what is best. Car is using loads of gas at moment ( 60 L gets about 130 miles) used to get 170 to 200 on same amount.

[Gilbertd]

I've just fitted a set of NGK Iridiums in my P38 Range Rover (same engine). It starts easier, runs smoother and seems to be using less gas too. The correct ones are BPR6EIX and I got them from here http://stores.ebay.co.uk/thecarpartswarehouse but there are a number of suppliers on eBay doing them for around £4.50 each (compared with £8 each at my local motor factors).

[mat_fenwick]

I would suggest that a 25% reduction in fuel economy indicates something else amiss rather than just time expired spark plugs, so perhaps needs more investigation once you've changed the plugs.