Backfiring and stalling

[general_lee]

Have just had the best (trouble free) weekend I've ever had in my two years of owning a 4.0 HC - top down most of it ... it having taken that long to sort out a host of starting / overheating problems. Today, my girlfriend took the car out shopping and before she got there it started to misfire and cut out when idling. It always restarted, but would continue to misfire / idle badly. Anyone got any ideas on what might have gone wrong. I changed the leads lately for a set of Lucas leads, but it's been fine since then (about 500 miles)and the AA chap checked to ensure none had worked loose. :grumpy