1997 LR Disco D1 having trouble with idle and starting. Idle normally @ 750 RPMs but occassionally it drops to 500 RPMs at start and runs very rough, usually smoothes out and and returns to normal RPMs after revving motor a couple of times, however sometimes it stalls. Recently got some questionable fuel but ran all but 1/4 tank of it out and refilled with new plus Lucas Fuel Additive. Trying to change fuel filter but having trouble removing the lines from the filter itself. Heard something about ****** ends on fuel lines going into filter. Would this prevent removal? Any suggestions would be appreciated !!!

 

Fuel filter needs some PB Blaster usually to allow things to open up. As you have found it, you know what a great location it is in for "clean living". But you could also need plugs and wires, IACV could need cleaning, throttle body, etc. There is a fuel pressure test point on the passenger side fuel rail (looks like tire valve). Would expect 32-34 PSI when running.

 

If you have the screw on fuel filter still then there are no b-a-r-b-e-d ends.
This is what should be there Fuel Filter (Part # ESR4065) - Land Rover gas filters from Atlantic British
This is the kit for fixing it if you had to cut the fuel lines Fuel Filter Kit - Land Rover gas filters from Atlantic British
If your fuel filter is rusted on so bad it wont come off you will need to split the nuts on the filter, thats what I had to do on mine.

Your idle issue it due to a dirty idle air control valve and throttle body.