Hey everyone;
I've got my 300tdi defender 110; been driving it daily, no issues, except the occasional fuel guage fault and water temp fault.
Anyways, i go and change the air filter, things are good; 2 minute job.
I go to start the truck up, but has a little more hesitation in the start; takes and extra few cranks to get er' running. Once it starts up, she goes great.
Take it down the street, and it starts to sputter, and nearly stalls, but takes a little coaxing to get it back up to drivable rpms.
Park it, start it up a couple hours later, all to the same picture.
Barely starts, sputters, runs for a few minutes then starts running rough again.
Is this just low on fuel, or could there be something else I'm looking at?
I thought that if a diesel was out of fuel and it sucks in air, it would just cut out and not start again. Is this true, or are the 300tdi's different?

Sounds more major than lack of diesel to me.

been working on it for a couple of hours now, and here is the latest.
it will start, run perfect...i then accelerate, and it winds up to a higher rev, then quickly chokes itself off to the point of stalling.
If i leave it at idle, it will just run really really rough for a minute, and the accelerator does nothing, until suddenly it starts going again.
Could it just be air in the lines?

Sounds like fuel issues to me. Have you changed the filter recently? Is the fuel tank breather clear?

Try putting the old air filter back first as thats when the problem started... a smidge of clean oil on the rubber air filter seal ensures a good seal.