What could it be? 240d - not starting

[chetwesley]

I am thinking of going to look at a 240d that was supposedly running fine and then just wouldn't start one day.

Apparently, it sounds like it is firing on a cylinder or two, but won't catch and stay running.

What would be all the possible causes of this problem? I assume it wouldn't be a problem with clogged filters, as it is getting enough fuel to fire on a cyl or two.

Valves needing adjustment? Anything else?

Odo is broken, so I don't know the actual mileage, unfortunately.