Only Emerson tagged me.... Really???
1998+ rangers have these known 'problem points':
Front suspension wear:
the upper ball joints are not replaceable
Control arm bushings go causing inner camber wear
Whole front rebuild cheap and easy (sub $200 in parts + an alignment) just a thing to be aware of
'the ranger lean':
They all lean to the left, the fuel tank strictly sits on the driver side... As does the 300lb delivery driver that used it the 10 years before you bought it.
If it bothers you, replace the leafs, reasonable cost, but you will break lots of rusty bolts.
4.0 SOHC:
Steer clear of early trucks, they like to eat timing belt tensioners
4.0 OHV:
Near bullet proof, very thirsty (MAYBE 15mpg in 4x4 trim)
Coil packs are prone to fail
3.0 OHV:
Gutless, also nearly bullet proof (surprisingly have a dead on in my garage)
Camshaft Syncros are prone to fail
4 bangers:
The OHV ones are gutless but reliable. The newer OHC ones are actually quite nice
Transmissions (auto) are prone to failure.
Manual Transmission V6 trucks - M5ODr2:
Very easy to bend shift forks, do not shift like you are imitating fast and the furious and it won't happen.
Rear spring shackles and hangers-
They rust BAD, super cheap to replace, and can be done with the bed on, but will be a rust-in-eyes filled event.
Pre-2000 4x4 front hubs- are Vacuum operated, and known to be problematic/finicky
Lastly, 5.0 SBF damn near bolts in from the 1996+ V8 explorers, which is the motor is should have come with from the factory.... I'm working on my SECOND V8 ranger right now.