Mr_Reverse

Check the brake fluid. If it is near min it will turn on the light to warn you to have the brakes inspected. As the pads wear down, the fluid gets lower and the fluid level sensor is set to turn on the light when the pads require replacement.

Just looked at your location info, if it is a local truck for you there in California, a passing emissions test will tell you that the fuel system is working properly.

Best thing is to test drive. If the truck is running poorly, or making squeeling or grinding noises, you are likely to have some issues that can be expensive. If running good and driving well, shouldn't be a big worry. Many shops offer a prepurchase inspection service and most sellers won't have an issue letting you have the inspection done. A seller that does have a problem letting you take it to a shop for an independent inspection is hiding something and not to be trusted. Like with all used cars, service and maintenance records are nice. The timing belt used in the 1987-1993 early production V6 was a 60k mile belt. Unless the truck was well maintained and treated well, after 30 years, you can expect a lot of work is going to be needed.

Simple thing is to drain the t-case first, do the work and then refill the t-case with fresh ATF when done. The fluid is probably due for replacement anyway.

Look for rust in the frame over the rear axle. Rust in the floor under the back seat and driver's floor. Manual trans needs fluid over fill to prevent input shaft bearing issues. The throttle body injection is not great and parts are hard to get any more.

That does assume that the seals are in good condition and not leaking. You will have some fluid leaking out of the transfer case when the rear drive shaft is removed.

You will either have the key programed by the dealership or a locksmith. It is a fun little game where you have to send info in to Nissan and the system will send back a code to allow key program for that particular BCM. You will also need to have all keys and inform the person doing the reprogram about the remote start key. If I recall correctly, there is a maximum of 4 key 'slots' in the security system, so only 3 keys plus the remote start can be programed. I had to do a lot of key program while at the dealership. It is not anything like what Hollywierd makes it look like.

Drive by wire does have some difficulty just off idle. I believe I read somewhere, possibly when I was working at the dealership that there was a lot of complaints about aggressive tip-in with the Titans when off road. I think that they had a programing update to change the throttle response when the truck was put into low range. I don't know if anything like that was done for others though. It might be more practical to practice 2 pedaling when crawling. My old 93 uses the old cable throttle but I still find using both pedals at the same time gives better control in some cases where I need more torque, but slow wheel speed. The R50 and most of the D22/WD22's are old enough that the brake signal override is pretty tolerant of applying brake and throttle at the same time.

I cannot visualize having full power to the socket until the light is plugged in. The voltage drops to 0 when the bulb is plugged in but showing 12+ when the bulb is unplugged? Does the ground wire have high resistance? Only safe way to power the right headlight off the left circuit is to build a harness that is using relays, powered off of the battery and triggered with the stock wiring. Pretty simple to build and does fix a few problems with the factory set up. The headlight switch will last pretty much forever and the headlights will be brighter due to getting full power rather than the lower power the factory set up provides to the bulbs.

Are you sure it is the rear main? Common leaks that seem like a rear main is the valve covers or the camshaft bore plug.

Crazy thought, but have you checked the fuses? The left and right headlights have their own fuse in the box under the hood.

My old 93 With the LT 31x10.50 15 was supposed to be at 26 psi cold. I run 28 for the street with my 33x12.50's. Do the chalk test to find the best pressure for your tire, wheel, truck combo. I would expect it to be in the 26-30 psi range.

In my experience, P420 and/or P430 have been failing cats. If there are other codes, I would resolve them first, but if no other codes, it has been the cats going bad. If you have an IR thermometer (non-contact type) the simple check for the catalyst health is to get the engine up to operating temp. Hold engine speed at 2000-2500 rpm for a minute. Let engine go back to idle and measure the temperature at both ends of the cat. A healthy catalyst will be at a minimum of 150°f hotter at the outlet than the inlet. If the temperature is nearly the same at both ends, the catalyst is worn out and not functioning properly anymore. If it is hotter on the inlet than the outlet, you have a restriction and the cat is bad. The upstream cats are the primary cats and the ones the ECU monitors for function. The downstream cats are reduction cats that are primarily for reduction of NOx. There are a few states that have California type emissions requirements, so finding California emissions across the country is quite common. Don't know anything about cataclean, but I am naturally suspicious of things like that being much more than snake oil. Catalyst failure used to be an uncommon problem. Used to see 1 or 2 per year, now I see a couple per month on average. Problem started getting noticable a couple years after E10 fuel became mandated across the country. The ethanol is not a good idea for our gasoline engines and does cause more than just corrosion issues in older cars and trucks. My 93 Pathfinder ECU is not programed for it. What it sees is a lean condition at the exhaust, so tends to richen the air/fuel mix to get the correct reading from it's O2 sensor. That causes fuel economy to go down and makes the catalyst work harder and hotter. Not good things in the real world. With the VQ engines, you have 2 O2 sensors that are after the cat, but the upstream sensors are actually fuel/air sensors. Similar to O2 sensors, but have a much wider measuring range and much more sensitive. Easy way to tell the difference is an O2 sensor will have up to 4 wires. An AF sensor will have 6.

The red, black, white wire harness is the O2 sensor. The other one should have wires for reverse, neutral, 4wd, and 5th gear(I think) switches. My computer died yesterday that had the FSM for my 93 in it. Monday, I can look it up at work on Alldata, but it shouldn't be too hard to follow the harness and see what all it goes to. Mine is automatic transmission and I have tinkered and altered so much of it that it is a poor guide. It doesn't even have an ignition lock anymore.

Is there a rattle when the engine is first started? If so, you might have an internal oil leak and or worn timing chain tensioners. Both are problems seen with the VQ engines after about 100k miles. The catalysts used on the VQ40 also had a problem with disintegrating and both clogging the down stream cats and even getting pulled into the cylinders causing damage to the engine. Best thing is to take it into a dealership for diagnosis, but if you are able to do the work yourself, unbolting the upstream cats and visual inspection will tell you if they are failing. If you have a boroscope, you can pull the fuel/air sensors and take a peak at the catalyst matrix, but it is hard to see doing it that way. All 3 of these problems will eventually set codes and turn on the MIL, but in the early stages often won't.

A lot of electrical differences between 92 and 94. 1992 had a mechanical speedometer and had a speed sensor in the speedometer head for the cruise control. 1994 used a speed sensor in the transfer case or transmission for the 2 wheel drive that ran the speedometer and shared the info with the cruise control and ECU. The wiring is different and not interchangeable. The transfer case wiring is for the 4wd light. The 4wd is strictly mechanical in our old trucks. The automatic transmission is electronically controlled so you do have a wire harness going down there as well as the O2 sensor. The O2 sensor wiring is its own harness that runs along the transmission harness.

Unfortunately, that is a common problem with the Pathfinders that have the VQ35 and a cable controlled throttle. Usually it is a small coolant leak at the throttle body that drips coolant onto the idle control valve. Over time the valve gets damaged and requires more current to operate and causes the idle control drivers to burn out in the ECU. Only real fix I know of is to repair/replace the ECU and replace the IAC valve. Make sure everything is clean and sealed. Things like the IAC valve are year specific even if the engine is the same because of the running changes that are done in the wiring and ECU. Often there are incompatibility issues just because of the emissions systems and programming.

Get the rear axle from a WD21 with the off road package and you get the tightest LSD and disc brakes, but then you have the abs issues...

That my friend is why my work boots are steel toes. Even though most of the shops I have worked in don't require them, I still wear steel toes because I know how clumsy I can be. Hope the toe heals quickly.

Oh yes, the bodylift makes working on the engine easier all around. If you still have the oil filter in the stock location on the VG30, it even makes filter replacement easier. Still messy and bad for the starter though.

About $25 at my local salvage yards and a little time. Lasted many years longer than the 3 stockers I got from the parts store. That is what the Quest alternator set me back. Back then it was $15 for the alt and I had to fab a mount for my old VG30 engine. Easier with the current engine in my truck.

I doubt you would have to trim the lift blocks. 1/2" is small and the bumper should line up fine. I have done both the 3" on my 93 and the 2" on a 95 a friend had. I honestly found the 3" to be a little easier and have no regrets. It has made working on the truck easier and #6 spark plug is easy to get at.

I put a light coating of molybdenum grease on the body of the bolt that is in the bushings. That helps prevent the bolt from seizing in the bushing. That makes future repairs easier.

I can't imagine the suspension links to cause any problems with the axle bearings. Are you sure the bearing is bad? I also don't see the bearing as being that expensive, more like $30 I think. They can be a bit of work to replace, and will require a replacement seal and retainer ring. The instructions in the manual has you drilling a hole in the retainer then using a chisel to break the retainer. Then using a bearing separator and a press to press the old bearing off. Assembly is stack the parts in proper order and press the bearing into place and the new retainer. Edit, I just remembered replacing the bearing and seal on the 95 my friend had. The retainer was not pressed on with his, it was a big nut that was screwed into the axle shaft. That was easier in that no cutting was involved and a press was not required, just makes it easier. Not sure which method your axle has.

I didn't bother tapping into a switched power for any of my e-fan conversions. They have all always been hot. The fans don't run enough to hurt the battery when the engine is off. If I was going to have it switched, I would pick a convenient circuit that isn't a critical one and use it to run a relay to feed the fan controller.