In United States we all love big trucks and some of the most famous 4wd SUVS & Trucks made by Toyota are Toyota 4 Runner that comes with 3VZ-E engine from 1988-95 model , 3RZ FE ( 2.7ltr) engine for 1995-2004 for the ones that has 4 cylinder engine and the one with V6 engine was 5VZ FE. Toyota Tundra & Tacoma also came with similar engines, which makes 3VZ-E, 5VZ, 3RZ & 2RZ ( 2.4 LTR) ENGINES one of the most popular engines for Toyota Vehicles.
Along with these Rear Wheel Drive motors Toyota Camry engines ( 3SFE, 5SFE, 2AZ FE) and Toyota Corolla engines for 1998-2007 up models ( 1ZZ FE ) are also very famous.
It has always been difficult to find such engines because junk yards in USA have limited quantities. We have noticed the only way to get such engines is to get Used Toyota Engines from Japan. In Japan due to strict transportation laws people don't drive more than five years. Japanese roads are better than the roads at home. People in Japan take their vehicles only to dealers to get it serviced. Most drive only on weekends because in Japan public transportation is cheap. Bullet train ride from Osaka to Tokyo costs $100, which is cheaper than driving the car, paying for gas & parking expenses as Parking is very expensive in Japan.
There are very few Companies who are importing such low mileage TOYOTA ENGINES from Japan. The only solution is to find such importers if you need a low mileage and tested engine for your Toyota. These importers run Compression, Leak down & Oil pressure test on these engines before they ship them, which ensures good quality.
In places like Texas, Arizona and New Orleans people drive a lot of trucks and all you will find is Toyota Tundras, Tacomas & 4Runners, therefore demand for such motors is bound to increase. Older engines will be difficult to find at junk yards as most don't have good, low mileage. Companies who stock a lot of Rear wheel drive engines for Toyota are bound to cash-in on their stock quickly.