Discovery V8i Lumpy Running

Well I was tinkering with my new pride and joy 97 Disco V8, knowing that it wasn't running quite right and the reason I got it for a good price. After checking all the sensors I checked the voltage on the MAF. Now this should be around 1.0 to 1.5 Volts, but mine was reading 3.3V !!!!!! no wonder it felt lumpy, drank fuel and sooted up new plugs in an instant. Well I set it to 1.3V which is a good starting point and it is a good deal smoother and more responsive but still doesn't quite feel right, so now I'm thinking ignition timing. If the MAF was that far out who knows what they have set the ignition timing to. Now I know you can't really trust the timing marks on the crank pulley so I'm tempted to just ease the distributor round until it sounds and feels better. Provided it doesn't pink on load it should be better than it feels now. At the moment it kind of shakes and doesn't feel free or wanting to rev. It seems to be firing on all eight. My gut tells me its too far advanced but I can't get it to pink. However, it is an Auto so its difficult to labour it. Any thoughts?

Urm.

It should be at 6 degrees btdc I think.

My 3.5 should be 0 degrees but runs sweetest at about 6/8 degrees on the crank. The timing chain will be stretched though so it's bound to be out!

Check compressions, check timing, make sure all the ignition components are in good nick. If there's bags of fuel (they're always bloody rich if theyve not got lambda sensors) and a good spark it should run quite well