Calling all Range Rover knowledge... please!

Hi all,

A mate has an '85 rangie (3.5l v8) with some problems we need to address. All aside it is an awesome truck that just needs some TLC.

There seems to be a fuel related issue with it at the moment. the consumption has gone right down (which isnt the problem), there seems to be a lack of power, it stalls occasionally and sporatically wont start.

It has been suggested to me that we should source a fuel pressure gauge & tap into the fuel lines after the pump to see what the pressure is and after the regulator to tell what the return pressure is. testing both of these mesures should indicate if the fuel pump or regulator has problems. is this true or urban myth?

If this is a true means to test fuel pressure, what pressue (or at least min pressure) should i be reading when the gauge is connected? the rangie has an aftermarket drop tank with external pump (i believe standard pumps for this model was inside the tank).

once fuel has been confirmed working we will go from there. she has a new airflow metre etc so air shouldnt be an issue.

she also has a terrible oil leak which appears to be rear mains seal. it is coming from the back of the motor. need to degrease it first and see exactly where it is leaking from. if it is the rear mains seal, how difficult would that be to do? is it a case of motor out? that is starting to head out of my league but we both have a no harm in trying to fix it ourselves attitude. all else fails call in the pros ;-) can changing this seal be done by obtaining and following a workshop manual?

thanks in advance,
Tom