Slartibartfast

Huh... a wobble that only happens at low speeds? And no shudder/death wobble at high speed? (And the wheel is bolted on properly?) Check if your rear axle says "LSD oil only" on it (orange sticker on the back). Ever replaced that oil? An LSD with non-LSD oil in it will bind/shudder, which would cause the tires to skid and drag a little on sharp low speed turns... that's all I can think of that you wouldn't feel at high speed too.

Auto trans or manual?

I'm not too familiar with the manual trans, but maybe a stick got jammed in there on your wheeling trip, and in first gear the shifter bends the stick, you let go, and the stick pops it out again?

I don't know anything about distributor differences in WD21s. Pics?

They said it's leaking because of the wiring harness? Maybe it's leaking around the connectors on the trans?

It could be that something is stuck in the HVAC system that's preventing the recirc door from sealing properly, or holding it open just a little. I know it's easy to get to on the WD21, not sure about the R50 though. Is there any wind noise or draft around the door jambs?

Sounds like a dead coil to me.

The knock sensor is supposed to tell the ECU when something on the motor is pinging, knocking, rattling... generally doing something it shouldn't. I think it's designed to detect predetonation or a rod knock, but I've heard (generally, not Pathy specific) of loose heat shields setting the buggers off. I think the test your mechanic was talking about was to hit it with a hammer and see if the engine speed and/or sound changed (which would indicate that the computer "heard" the knock and held the motor back a little). It sounds like the ECU can tell "no signal from the knock sensor" from "knock sensor senses a knock." Odd (and unhelpful!) that it would throw the same code for both.

I looked in the '89 FSM (don't remember where I got it, found the download link around here a while ago) and found the plug on EF&EC-21. Looks like the wire with the corroded pin is labelled 103 and is "B/L" ("B" is black, "L" is blue because... ) and it goes to Joint Connector A, which--near as I can tell--is just a jumper block that connects that wire to several others, and it looks like some of the others go to sensors. That sounds like a ground to me, but it's not hooked to body ground, so maybe it's a regulated ground for the sensors? Here's most of that page. The plug is the one labelled 262M. No way that pin's coming out. The one in the plug might, but then you'd have to find a new one. There's probably some kind of electrical cleaner made for this. I would start with contact cleaner, and when that did nothing whatsoever, I'd scrape at it with a very small flathead screwdriver, maybe some very fine sandpaper on a stick, spray it again, put some dielectric grease in there, and plug it back in. Weird how it's just the one that corroded.

What's your heater/air conditioner set on? If it's on 'fresh' it'll suck air in from outside, even if the fan's not on. Set it to recirculate and it shouldn't do that unless the little flaps aren't sealing right.

I think I just posted in your intro thread. ECU and harness should be the same, or compatible at least. It's basically the same motor so it should run off either computer, and AFAIK the connectors didn't change. Consider doing seals/spark plugs/etc while the motor is out!

Took it out for its first drive after cleaning the TB/doing the vac lines. I'm not sure which one it needed, but something sure made a difference! It's still not the fastest thing on the road, but it pulls harder and what I thought was an exhaust leak is gone too. That made me happy. Then I pulled into a parking lot and the engine forgot to idle and stalled out again. Stupid intermittent issues! Tearing into the IACV and the TPS tonight.

The fuel pump can't empty the tank completely, there's no sump on it, so it just sucks until the level's lower than the pickup. A "running on empty" fillup for me is 16-18, and I verified that my tank was 21 gallons when I put it in. I suppose this means that, if you run out of gas in the middle of nowhere, you could pour a couple bags of pebbles or little glass marbles or something down the filler, displace the fuel/raise the level to the height of the pump, and thereby limp it out of banjo territory.

Well there's your problem!

Did your overhaul include the rear link bushings?

Maybe Rob (Alkorahil) can source one. Have you tried testing it? Three switched pins sounds like it's got a normally open and a normally closed, so be careful you don't put power to the normally closed instead of the coil. If it's not the relay, it could well be that a previous owner got as tired of that little beeping SOB as I did and cut a wire somewhere.

Think those are original? I did wonder a bit about the wrapping. Anyone know if Sumitomo was the OEM for plug wires? KDJ, sorry to hear the glue fix crapped out already.

If it's just vapor getting out from the top of the tank, I wouldn't expect to see much.

That sounds infuriating.

Maybe the seal between the pump and the tank has split? If you don't find a smoke machine, or they're really proud of it, you could probably rig up a redneck smoke machine with some dry ice and a bucket.

Mine did its stall-instead-of-warm-idle routine again, which as usual cleared up after I messed with a few plugs. I figured I'd pull out the coolant temp sensors and clean them better, maybe clean a few other things up, check some wiring... So of course I tore into the throttle body, the EGR, the vacuum lines, and a couple other things that got in the way. I'm fairly sure the EGR valve is supposed to have threads there.

Good to know! Disregard my speculation.

Make sure you know when the timing belt was done last, and if you don't know, do it or have it done. A timing belt run too far past its change interval can fail and bend the valves. Good to check/change fluids if that hasn't been done. Tranny fluid (assuming auto trans) should be red, dark/burned/gritty fluid would mean tranny problems. Oil leaks aren't uncommon, could just be the valve cover gaskets. Take a look around the front strut towers for rust (not likely a problem in California). It should be a pretty solid rig, but as with anything that's got 200k on the clock, keep an eye on it and expect to fix a few things.

Doesn't sound good, whatever it is. I would drop the drive belts (steering pump/air conditioner/alty) one at a time, start it, see if it still makes the noise. If one belt makes the noise go away, you can check out whatever's on that belt rather than diving into the engine. As for the wobbling, if the crank pulley is on right, maybe the harmonic balancer is shot?

Some degree of resistance is probably designed in so the hubs can't rattle into or out of lock if seated improperly or bumped.