Possible Ignition Problems on Mondeo 1994?

I have a 1994 Mondeo 2.0 Automatic and it appears to have developed an ignition fault of some kind. Originally in idle the engine was hunting, then it also started cutting out altogether both when in idle and when moving. Now although the engine starts up it immediately cuts out again. Has anybody else had a similar problem? And if so does anyone know of a solution, It has supposedly been on the Crypton tuner and I am told it does not show up anything. They now tell me they would like the car for up to 3 days to check every circuit which could cost up to £400 before they actually find the fault. Any help would be gratefully received.

Peter Taylor
September 2006