Slartibartfast

I'm not familiar with the chip key setup on the R50s, but I would see if there's an obvious screw or battery compartment on the dongle. Might just need a coin cell battery swapped out.

Looks pretty straight, at least! Bad paint just means you don't have to worry so much about it. I see that missing door handle, those are always fun. The forum isn't really built for hosting pictures. Better to host elsewhere and link them in. No size limit that way. Paste in the link and it auto-embeds. I've got mine on Flickr, but there's probably a better option. Let us know what you come up with for the rack! I've been designing one in my head for a while. Naturally I haven't gotten around to building the thing.

@Lock manual swapped a VQ R50. I have not heard of anyone else pulling it off, so if you want to go that way, that's who you need to talk to.

The same sensor died in mine, started faulting out whenever it got wet. When I saw the price of a new one, I decided I didn't need ABS. Looks like the price has about doubled since then, holy crap.

Well that sucks! You might get away with a little exacto knife action on that adapter plug. Splicing means you've got one less connector to give you problems, though.

Sucks about the surprise baptism, but better for it to happen in the shop than on the road!

I'm honestly not sure when ABS started in these, and whether it was a trim thing or a federal thing. The part numbers for the ABS valve block go back to '90, but it's not in the '90 manual. If yours has it, the valve block is under the truck, on the inside of the passenger's side frame rail, sorta under the passenger's seat area IIRC. Should be an aluminum casting with a bleeder, an electrical plug, and two brake lines going into it. The control computer for mine was under the driver's seat, but IIRC '92 (and earlier?) had it under the stereo. The sensor reads from the pinion flange on the rear axle. If yours doesn't have it, you're not missing much. All it does is release the rear brakes if it sees them lock up. There's no pulse action, no pump, no improved stopping distance. It's just trying to stop the rear end from stepping out and potentially rolling the truck. I guess if road conditions are bad enough to allow the rear brakes to lock, and the driver doesn't know to pump the pedal to regain control, then it's safer to nerf the rears, keep it straight, and take the hit in the crumple zone.

I haven't heard much good about aftermarket distributors, so if they'll sell it separate from the engine, that would be a good thing to have on the shelf. If the fuel tank doesn't smell like something died in it, consider the fuel pump/level sender assembly as well. There's an access plate in the floor above it, so you don't have to drop the tank. Round-dash headlight and wiper stalks will not work on a square-dash column without extensive screwing around. (I looked into this for mine, because I've got two sets of round dash switches in my stash, and decided it would require more butchery than I wanted to get into.) A square-dash cruise control headlight stalk should fit a square-dash non-cruise truck just fine. It'll just have a second plug that doesn't go to anything. It's possible to add intermittent wipers if yours doesn't have them. IIRC the amp is the brown box on top of the wiper motor. There's probably a writeup for the swap on Infamous Nissan that'll tell you what all you need. Are you missing any clips? Fasteners? I grab any hardware I take off, plus whatever is left around loose. The metal clips for the plugs in the engine bay are easy to lose, might as well grab a few of those with the injectors. Might be worth grabbing some spare relays, too. I paid $2 each (about ten years ago!) for a pair of factory blue relays, which have been running my headlights since. Tail lights are surprisingly expensive for these. One of mine has a small crack in it, so I'd be on the lookout for those. And yeah, if you find a front door arm rest that isn't cracked like a dry lake bed, grab that SOB. Make sure you know how the yard operates (and charges!) before you start pulling things apart. Some yards may not want you to break up what they consider an assembly. (Might not want to sell a door handle, if they think they can sell the whole door.) One yard I went to wanted to charge me for a whole steering column, when all I needed was the headlight switch. Hopefully yours is less uptight.

Oil consumption is unfortunately common with the early VQs. My dad had a similar experience with his '03. I have read a lot of speculation as to what causes it, but I don't think I've ever seen a smoking gun, or a "this fixed it" story. My dad had a PCV put on his, which didn't help. The local mechanic didn't want to tear into it. Synthetic oil made the smoke on hot starts a little less visible, but didn't change the rate of consumption. He ended up selling it to a guy who had an engine from a wrecked one. A lot changed across the early years of the VQ, and between platforms, so your list of possible donors is quite short. I remember someone laying out which years were compatible, but naturally I can't remember enough about that thread to find it again. I think '03/'04 R50 are the same, but do your research. P0021 means the computer lost control of one of the cam phasers. The cam phasers are actuated by oil pressure, so yeah, that makes sense. The source of the coolant leak might be more obvious from underneath. I would also check for leaks at the coolant crossover pipe (between the heads, at the back). Might need a mirror on a stick for that one.

Sure, but generally it's easier if you tell us what's wrong with it!

That's a weird one. Having to start it with carb cleaner makes me think it's not getting much fuel. Do you hear the fuel pump prime when you turn the key? Did you replace the crank sensor (on the back) or the cam sensor (in the distributor)? If it was the cam sensor, you'll need to set the ignition timing. The crank sensor is only there for misfire detection, so that shouldn't be able to make it run weird. Check that no wiring got pinched between the engine and trans when you bolted them back together. Any OBD codes?

LOL yeah, that could be it. Five easy ones to really make the tricky one stand out. My beef with #6 comes mostly from trying to get a compression tester into that hole.

The fuel smell is interesting. Might just be because there's fuel in the intake manifold. Just for grins, pull that vac line back off, and cycle the key a few times (to the run position, wait for the fuel pump to stop, then turn it back off). That should remove any doubt about whether the reg is leaking. I could swear I'd found an injector leak test in the manual before, but I'm not seeing it now. Unfortunately there's no test port for a fuel pressure gauge, so you'll have to tee one in. Release the fuel pressure first (fuel pump fuse out, run the engine until it stalls, crank a couple times to be sure) so you don't spray gas from hell to breakfast when you open the system. Fuel pressure should be around 34 psi at idle with the vac line to the reg connected, 43 with it disconnected. Then shut it off and see how fast the needle falls. I've seen a couple of sources quote 10 PSI in ten seconds as the cutoff, but I'm not sure where they got that number. With that said, if one injector was leaking, I would expect one black plug. I would not expect six bad injectors, unless the last guy replaced all six with the cheap crap ones. Six black plugs has me thinking the computer is injecting that much fuel based on bad info, which brings me back to ground you've already covered. I know you've already done the coolant temp sensor, but I would go through the troubleshooting in the manual for that sensor/circuit anyway. Make sure the sensor is in spec, and make sure there isn't a wiring issue between it and the computer. Rule it out right proper. I'm not quite following here. Hard starting, extended cranking? Does it start more easily when it's warm? Might be worth throwing a new connector at it, on the off chance. Mine had a loose MAF connector, and surged/stalled at warm idle, especially stopped with the transmission in gear. I couldn't make it act up by jiggling the connector, but when it was acting up, jiggling it usually cleared it up. It's been fine since I replaced the connector (Rockauto had a replacement pigtail for it). Your symptoms don't sound like what mine was doing, though it sounds like it can manifest differently in some cases (see Precise1's second post in the thread linked below). There was a plug-in harness with a ground lug to fix this issue. My donor car had one. I swapped it into mine, and to my surprise it ran like absolute crap until I took it back out. I still have no idea why. Possibly the loose connector fit worse in the repair harness than it did on the sensor itself? I decided I didn't need to poke that bear.

Good to see I'm not the only one exploring random rabbit holes. Your conclusion sounds reasonable to me. And yeah, I don't see why ATF wouldn't work. That's what the Tremec T-5 in my dad's hot rod takes.

I've heard of people jacking up one side/parking on a slope so the fill hole is higher. Might be worth a shot.