Power issues on 3.9 V8

Hi guys,
I'd like to pick the brains of some of the experienced Land Rover owners who will be floating about here.

Of late my Discovery has been taking an awful long time to start and I wasn't sure why, it would rasp as if it was about to burst into life, only to quieten down again to the sound of the turning of the engine.

Tonight, whilst out on Salisbury plain (just beyond the redhorn vedette) it conked out and after about 30 mins I managed to get it going again but now when the accelerator is depressed the revs drop off which, I'm sure you'll agree, is a sure sign that something is awry.

When I pumped this into google I found someone with a Ford Capris had had a similar issue and the people on that forum suggested fuel injection, however I wanted to come and put this question before you as you'll be the ones who know about Land Rovers.

If anyone has any suggestion of things for me to do then I'd love to hear them.

Cheers,
Ollie

Obvious one is to check for air leaks around the plenum.
Has the vac hose for the dizzy popped off for starters? etc etc...

As u are specific on the area u had this issue do you think this should be taken into consideration?.
If you believe it's only your engine that has an issue then the usual checks will be required.
If you are unsure what to check then let the forum know and we can take it from there.

I'm absolutely a novice.

I'll check the vac hose, I am currently looking at how to check the fuel filter which I gather is somewhere near the tank and slides out, I think I'll also give the engine bay a wash down so I can see what's going on better.

Do you think I'm in the rough ballpark here, and that it could well be a problem with fuel injectors/ fuel/ combustion or does it sound like something different?

Thankyou for replying guys, I just hope I can get the old girl going again as a) I need her for work (agricultural fencing at the moment) and b) I genuinely love her to bits

Cheers,
Ollie

Simple things first.

The coil top connections can a bit iffy, they get dirty and also become loose so that's where I'd start so clean them so they are bright and tight, also look at the air filter if dirty replace it.
You can't test you fuel-filter but if the mileage use is unknown then replace it, it positioned behind the rear off side wheel and is a bit off a task to change, it looks easy with just two glands and a bracket to undo.
Crankcase-breather often called a 'flame trap' should be clean just unscrew and wash in petrol along with it's hose to the plenum.

And get yourself a Haynes manual as most of what u need to know is there.

You will be extremely lucky if you can change the fuel filter by simply undoing the unions. Mine hadn't been changed 'in some while' and I had to replace a fair bit of the piping either side of the filter to make it serviceable.
I used unions and adaptors from Merlin Motorsport to solve the problem and make the filter much easier to change in the future.
The V8s are very sensitive to HT lead condition and age. It's also worth cleaning the MAF with one of the aerosol cleaners from Halfords. Mine was running fairly well anyway but the cleaning made the cold start and running even better.

Ok to tell you about it so far, I took the stepper motor out, cleaned it and attached it again and that helped with the revs, it had actually shaken very loose.

As for the not starting, a tickety sound that was occurring got louder and my head gasket went. Perhaps it was already blowing causing a reduction in compression and therefore combustion. It's just a thought as to what could be the issue. I'll know when I get it in a workshop, as of right now I've misplaced my only fob and the immobiliser is doing a sterling job and as such my Discovery has spent the last 8 days in a field where I've been building paddocks.

My luck is not great at the moment, as you can well see.