Are there any lights on the dash?
Engine management light's been on for years with car running ok! Confusingly the problem started the other night when the card died at traffic lights. Breakdown guy found no output from alternator and flat battery. Recovered home and recovered again to auto electrician, both recovery drivers commented on how rough it was running when they loaded it. Went to pick it up from auto electrician today (was slipping belt, not alternator) and it was running like a dog, so had it recovered back home again! Auto electrician reckons it must be coincidence that slipping belt and whatever else is happening happened at the same time. I'm now wondering if low battery could have caused a problem with a nearly failing fuel pump?? (I'm no mechanic!)
Have you tried unplugging the mass air flow?
No. Can a MAF fail suddenly?