Spencer,
I understand your pain, I feel the same way about mechanical problems. Electricals I actually enjoy solving them, Electronic ones HeeeHahh Honey, Where's the oscilloscope?
Irregular idle related to temperature is related to sensor and ecu. The cheapest is to change the sensor. Next is to check the ecu for copper tracks/solder/blown resistors faults. Here it gets into the pita because it's hard to replicate the conditions while you are testing the ecu.
The best bet is to get a buddy that will let you swap the electronic parts and see if his (or better yet her) car displays the same problems.
Friends help you move, good friends lend you their land rovers.

SD

 

That should be very interesting. You might consider adding a support vehicle for the support vehicle, Justin Case. You should have one with a big mobile grill and built in coolers.

 

Yeah, my wife asked who was going to support the Disco...

I guess my bro could bring his '56 CJ along...or his spitfire...

 

I will say this about the truck. It is totally unstoppable, even besides its design flaws. It's super cool, and I love to drive it when it's all working. It has way more traction in bad weather than any other vehicle I've ever driven, and the handling absolutely smokes any other four wheel drive vehicle that I've owned. And I'm from Minnesota, I've always owned some sort of 4x4.
I'm just too poor to work on mine right now, and I may be a little bitter about it.

 

That's exactly what I'm saying.
Some of you guys talk about getting $1000 Disco's all day long. It makes me jealous, because in this area, that will get you a busted up parts truck. I found only three DI's available on CL in a 200 miles radius of me (OKC, Wichita and KC). The cheapest one was $1600, and it had a blown motor (thrown rod). The pricier one was nothing special, for $4950.

Here's the KBB pricing report for my truck in my zip code. $4520 for a truck in good condition.

1997 Land Rover Discovery - Private Party Pricing Report - Kelley Blue Book

 

Same here, I have no idea where these guys find $1000 Disco's that are worth anything other than scrap.
I have found one so far, and I bought it for parts and I have already got my money back.

 

So if you completely resolve the issues, Why sell it?

Souded like you want to bail on it, you said it has been in the garage more than you have been able to drive it. I find this to be a little bit puzzling truly.

So you guarantee it is in Good Condition and even give them a 20 dollar discount, WOW. What a deal, how long a warranty are you providing on the "Good Condition".

Sorry I could not resist, please take it in good humour. Or "Here's Your LinK"

 

After pretty much rebuilding the cooling system, and doing the front end CV joints and wheel bearings(all of which probably took five times longer than it should have, because I did it all myself in what VERY little spare time I have), I've been driving it semi-daily for the last couple of months.

If I sell the vehicle, I naturally want to sell it for more than I paid for it. I'm not just looking to off-load it. That implies that I need to sell it in better condition than it was when I bought it. There were some nuisance issues with it when I bought it that I haven't been able to get to because other things have cropped up which took time, effort and money away from fixing the other things. But like I said, it's basically one replacement set of tires away from being back to a presentable daily driver status again. But that being said, first impressions are hard to shake, and this particular vehicle has not done itself any favors in that department. Maybe that's just bad luck. Who can say?

So why go to all that trouble to fix it up and just get rid of it? Here's an analogy that I see happen with my wife: she spends all afternoon making a large dinner, say for Thanksgiving, and then by the time it's finally done, she's not even interested in eating the perfectly good meal, because she just spent so much dang time working to get it ready, that it's no longer appetizing. That's kind of how I feel with this truck.