When shopping for Pathfinders (excluding 2001 model), you will probably notice that the truck has stayed just about the same (including the identical engine) from 1990 - 2000. This is a testament to the quality of the truck's construction and the early evolution of its design.
I've driven a 1994 Pathfinder for about 3 years now and it has been very reliable. As could be expected, I've had the front brakes ($300 non-dealership, $500 dealership), timing belt ($600 non dealership $700 dealership) and tires ($400) replaced. I should note that the original General Grabber tires lasted over $70,000 miles. I put a new set of the same tires on and, not only were they the least expensive tire on the market, they still look and perform great after another 20,000 miles. That was all routine maintenance. Not routine, however, were the problems I had with my exhaust manifolds.
As I came to find out at 70,000 then again at 90,000 miles, Nissan manufactured their exhaust manifolds (2 of them per engine)incorrectly. Over time, the manifolds warped away from the engine which led ultimately to breakage of the bolts which attach the manifold to the engine. It's not a catastrophic failure, meaning that the only real problem with the warping/bolts breaking is that the engine sounds like a diesel until you have the manifolds replaced. The repair costs about $700 per manifold.
Two very important notes on the manifold repair: First, if you have an extended warranty, be very careful about what your service advisor says to the warranty company. If he/she tells the warranty company that the bolts broke, the warranty will refuse to pay since most do not cover bolts. However, if the advisor tells the warranty company that the manifold is warped and the bolts have not broken, the warranty company will cover most/all of the repair. Second, Nissan has had a number of "service campaigns" on this problem. Best as I can tell, this is one step short of a recall of the engines. Nissan did not advertise these campaigns, however, so very few Pathfinder owners ever were served by them. So, you may find success by filing a complaint with Nissan corporate. The first time I did this, Nissan covered a large portion of the repair. They denied my complaint about the second manifold. It seemed to me that the honorable thing to do would be for Nissan to repair both manifolds at no cost since it was their repeated manufacturing error that caused the defect. In their defense, at least they repaired the first one for me at a lower cost.
Overall, the truck is great. If I were to buy another one of the same era, I would make sure the exhaust manifolds had already been replaced.
A few final notes: If you're looking at a Pathfinder with the sport package including the adjustable shocks, I was told by a repair shop that they cost $500 each to replace. At about $90,000 miles, the gas-powered supports for the rear hatch run out of gas.