Slartibartfast

Auto or manual? If it's auto, and it's shifting normally, that would suggest the trans computer knows what's going on even if the engine computer and gauge did not, which might help narrow it down. If it's manual, well, there's that theory shot. And, yeah, go get the '97 manual from Nicoclub. Should be some troubleshooting or at least a circuit diagram in the EL section. There's a lot of hand-holding for using the special dealer Consult tool, but there's usually an alternate method for the rest of us. If the sensor is good (and so is the gear that drives it), and both the cluster and the computer say they're not seeing anything, that would have me looking for a wiring fault in between them.

That is a weird one. If it runs normally once it does start, I doubt it's the filter. Any codes, any other issues once it's going?

Looks like they are still out there. No way I'm paying that for one, though.

I keep looking at the hockey tape on my arm rest and thinking there's gotta be enough of us left to make reproducing those worthwhile. I've even had "how hard could it be" thoughts involving silicone molds and foam in a can. Then I think about how long that would take, and what I'd be willing to pay for an armrest, and remember why mine's got hockey tape on it. I've been surprised at what's available for more popular platforms, though of course not all of the repop parts actually fit. That said, availability for these could be a whole lot worse. Try finding parts for a '59 Triumph 10 wagon. Reminds me, someone on an IH forum I'm on found a substitute for the hard-to-find rear window motor for the Scout II. His donor was a Studebaker Avanti. I told him that's like a cooking show saying, if you can't find unicorn steak, jackalope will do.

Here's what I've got. No idea if it's right for your application.

I'm not normally a fan of painting headlights, but IMO that look suits it. Breaks up some of that chromed plastic where it's not doing anything. Not sure about the grille. I replaced the emblem on mine with a rubber rat's head, though, so maybe I'm not the guy to talk to about tasteful grille mods.

I have no idea. Until I saw that in the manual, I didn't even know U joints were adjustable. Looks like some heavy duty Dana/Spicer joints require shimming, so maybe this isn't as weird as I think it is. Something to ask the shop doing the job. But, yeah, I had the same thought, that not setting these up right might be behind some of the stubborn vibration issues I've seen on here.

Looks like the above links are dead. Here's what I've got.

Got curious and checked the manual again. Looks like the snap rings for the U joints are also shims, and you select different snap rings to get the axial play into spec. The manual has part numbers for various thicknesses. No idea how you'd know what to order before getting into it. I don't know if anyone actually bothers with this, but I would at least check the play before putting it back in. PD section of the FSM.

I don't know driveshafts well enough to judge how much slop is too much, and I don't see a spec in the manual (though it does spec total runout at 0.6mm). The only truly bad one I've seen was in our '63 Scout, and that thing was so whupped it was sagging in the middle. I wouldn't expect an IFS truck to put enough stress on the slip joint to wear it out. If you can't make it go clunk wiggling it by hand, I would call it good enough--but, again, I'm not a driveshaft guy. I have heard of driveshaft weights coming off, though not on one of these that I can remember. I would expect to see an obvious bare spot and busted welds where the weight used to be if this had happened. The diff bushing symptoms don't match yours from what I remember. Just something to check while you're in the neighborhood.

Hey, mine only makes a dismal moan on right turns! Damned if I know why, I've done all four wheel bearings.

Good thinking trying the old wheels again for a sanity check. If it's fine with the old wheels, I would try swapping the new ones around to different positions to see if you can make the wobble better or worse, in hopes of tracking the problem to a fault with a single wheel.

Unless the joints are so flogged that they've eaten into the yokes, or the driveshaft has obvious dents/chowder marks/slop in the slip joint, I would just throw a set of joints at it and see where that gets you. Check your front diff bushings while you're in there, I remember someone on here had a vibration that came down to the diff flopping around under load and putting the joint at weird angles.

I'm not a tire guy either, but I have not had any wobble issues with the 31" tires on my '93, despite them being mounted and balanced by muppets. "They just do that" sounds like an excuse. I'm not familiar with hub spacers, but I would check the fit on those. No use having a balanced wheel if it's mounted off-center. +1 on checking the wheels for runout. If the wheels look okay, check the tires too. A damaged or defective tire could have a high spot in the tread even if the wheel is true. Have a look at the front end bushings (control arms and rack) while you're under there if those weren't on your list before. All four wheels being out of balance the second time is odd. Check your wheel weights. When I had mine mounted/balanced, the muppets used the wrong kind of weights for the rims. One actually fell off in my hand when I went to put the wheels on. Had I run them like that, I'm sure I would've had wobble for days. I wouldn't expect a domestic steel rim to trip them up, but I didn't expect the local shop to send mine home with the weights falling off, either. Hopefully tire shop #2 is better at what they do.

The usual/easiest swap is the VG33 from the early R50 Pathfinder, first-gen Xterra, or first-gen Frontier. It runs off the stock computer if you keep your old intake. You can keep the V belts using an adapter, or use the VG33's flat belts instead (easier if your donor is an X or Fronty). This thread covers boring and porting a 3.3 for more power and swapping it into a WD21. Lots of good info there, even if you're not going as far as he did. IIRC someone tried putting a Nissan VH45DE V8 in one of these, but it didn't work out. I've seen GM 3800, 4.3l, and LT1 engines swapped in, though. And of course people whack turbos and supers on VGs too. Are you sure the trans donor was an '06? I thought those only fit up to '04.

Here's one. Not sure why eBay brings up headlight switches and old-school floor-mount dip switches. Something something algorithm.

Pretty sure it was eBay.

The pulleys aren't keyed to the balancer, so they're commonly assembled the wrong way around, and you'll never know until you go to set the timing. IIRC it's just held to the balancer by six bolts, so it shouldn't take long to put it back where it should be so you can time it with a light.

PM'd.

Does sound like a loose connection somewhere. Check battery terminals, fuse links. If the terminals are alright, try to work out which systems are affected when it acts up. Headlights? Radio? A group of affected circuits could lead you to a shared fuse/fuse link/ground. If it's losing everything at once, that points back at battery terminals or cables. Can you make it act up by wiggling wires while the truck is parked? And yeah, I doubt it's related to your P0420.

Entirely possible. If so, it was pretty well done.

I've never taken one of these clamshells off where the plastic wasn't either gone or well on its way, though to be fair that's a sample size of four. And, yeah, those plastic trim screws are the worst. After buggering a few of them I realized you've gotta use a flat-blade screwdriver with as little down force as possible. If it's slipping, hook a fingernail under the head as soon as it lifts. An early HB I scavenged had regular metal screws into plastic inserts, like how the front corner lamps mount, not sure why they moved away from that. Good luck with the bearings. If you still want to borrow that socket, I think the pass opened this week.

The column covers always do that. Weak brittle screw posts. Probably doesn't help that it's in a prime spot to get smacked by knees. Mine wasn't worth putting back on, so I made a metal one instead. It ain't pretty, but it's stout. Can't help with the fungus, that's nasty. Hopefully there isn't a great gob of that inside the switch.

Throttle body and MAF would've been my first checks too. I don't know the 3.3 idle control system very well, but that's what I would check next. There's a wax motor that is supposed to crack the throttle open for fast idle when cold. EC-27 and 28 in the '97 manual show a procedure to check and adjust it. There's also an idle control valve controlled by the computer, but if that was going I think you'd have issues all the time, not just on cold starts.

When I replaced my soft lines, I cut the ends off the old hoses and welded them up to make caps. Overkill for sure but it works great. You can also prop the gas pedal down a little (a photography monopod works great for this) so the master blocks fluid from draining, though I haven't used this method in a while. I prefer knowing air can't get in there even if it wanted to.