I think the thermostat is getting stuck open; the engine takes forever to warm up, and never gets 100% to operating temp.
Due to neglect, the engine is dirty because of insufficient oil changes.
Also due to neglect, it has about a half-dozen vacuum leaks.
Muffler fell off at somewhere around 228,800 miles.
The truck has been dropped 3 inches, and because of it, you feel every bump and crack in the road and then some.
I am pretty sure that at least one motor mount (maybe a tranny mount) has gone bad. The truck 'wobbles' around 35-40mph.
I noticed the engine has a tendency to backfire around 2000 RPM when cold; might have something to do with the distributor advancement.
First off, I currently have this (86 D21 Hardbody) and a project 79 Mustang. Prior to these cars I have had 6 cars in the last 2-3 years (mostly all were "lemons"). In all of these cars I have owned, I missed none more than my 1984 Toyota Truck (Hilux) - my Toyota was a physical POS (missing both front fenders, grille, and headlights), but underneath the hood was both a beauty and a beast. I had searched for a replacement that I hoped I would like just as much, if not more, than my old 'Yota... Well, this Nissan is as close as I have gotten.
This car can be peppy; I was once carried 2nd gear from 15mph to 55mph, and the engine didn't sound anywhere near its redline.
The truck has potential to be an econo-truck. I got 14-1/2 US MPG a couple tanks ago, and got 17-1/2 US MPG on my last tank. This is with a half-dozen vacuum leaks and driving mostly on a cold engine.
Handles great, even for being dropped 3 inches. The rear leaf-springs sit about 2 inches above the ground. My friend took one look at the lowering blocks and the leaf springs, and said "the first time it snows, you ARE going to get stuck"... I drove in 4 inch untrodden snow with no problem; in fact, I had very little tire slip.
Plan to use this truck for some cross-country driving/traveling once I get out of school and fix some things on it. I may even try it as a hunting rig.