3.9 efi v8 fueling issue

Had my big old v8 up and running for a couple weeks now but I’ve noticed some strange things. It’ll start up in warm weather (5-10 degrees) but not at all in cold weather. Like in the snow recently. It’ll crank, it’s getting spark and fuel, but it won’t even try and splutter or anything.
When I had it running a few days ago it would idle fine in park but if you moved into drive it would start reving up and down randomly and if you tried to drive it it would sometimes stall. I also had to ease into revs because if floored it it would stall.

It’s a 1998 3.9 efi v8 with a brand new fuel pump and new ht leads.

Ok “fuelling issue” so what tests did u do to suggest that?

I’m sorry but I don’t know much about V8 fuelling as I’ve never had problems with them... even though I’ve own four of them.

When you move the selector from P into D there’s a load placed on the engine, which I’m sure u know, therefore the engine revs would drop if it wasn’t for the idle control valve quickly doing a readjustment, the valve can interfere with starting if not functioning correctly.
So I would could start by removing the valve and cleaning inside, if required, also checking the electrical connection.
I assume you checked all the ignition electrics for dampness, the dizzy and the coil terminals are spotless, and also the spark plugs are ok and leads aren’t touching and kept separate
When my disco use to misbehave I would empty a bottle Redex or similar into into the fuel tank which soon cleared any issues with engine idle, so that’s a quick job I do now once a year that keeps the idle perfect as it can be.

Hope that helps

So I pulled the plugs out, they’re pretty black and oily, switched them over on the bugger started right up, not even the slightest hesitation. But the idling issue remained. Seeing as I’d just replaced all of the ignition coils and it’d been a pretty dry week I was sure it wasn’t damp electrics.

A few days ago I went to pick up a few parts of a guy that was breaking his old v8 and while I was there I remembered what you’d said about the idle control valve and asked if I could have his, which along with a new fuel pump, snorkel, power steering pump and headlights, he was happy to give me for a really good price.
Got back, stuck the new valve in, cleared out the connector, started her up and now she runs like a dream.

Also shoved a bit of redex in there for good measure.
Cheers for the help discool, got me up and running again.

Well done, now enjoy. It just shows you how things are so easy with the D1 to fix, just the same with the early RRs.
But then the 2nd generation electronics was introduced by LR that now causing issues years on