Land Rover Repair: 1995 Discovery - bad idle, slow acceleration, mass air meter, catalysts

Question
I am looking to buy a 1995 discovery which is being sold for 2000 dollars. This is a good deal, but the engine is running very rough. It idles poorly and the truck shakes when you start to accelerate. The shakes stop when you get the rpms up and are going faster, but there is still NO POWER - it feels like its running on one cylinder - I could barely get the truck up to 30 mph. What kind of problems could I be looking at?  

Answer
Bad plugs and wires / bad coil / plugged injectors / burnt valves / plugged catalysts / bad mass air meter . . . it could be anything.

If it's for sale cheap, someone probably told him it needs a $4000 repair so he figures to look dumb and pass it off on someone else.