Engine Performance problem
1991 Land Rover Discovery V8 Four Wheel Drive Manual 160000 miles

1991 petrol v8i discovery runs great then suddenly rough, hesitates and sometimes stalls...if I park up and uncouple electrics from MAF it will settle...I remove fuel pump fuse for a few seconds then replace, then replug the MAF and she runs...until the next time! Every trip is Russian roulette. Big smell of petrol though- car has had new dist.cap and leads/plugs /air fliter/etc. Like a mini in wet weather! HELP please...