The poll is simple, pick which part/reason best fits your situation. If you upgraded it, pick that, if it failed, pick that, if you didn't know about it... and so on. As this builds, I'll post when most items failed (we'll use miy experiences in the mean time) and make links to posts/sites to help you get back on track.

Topics:
Water pump removal (http://www.rangerpowersports.com/forum/showthread.php?p=1451056) (it's not as easy as you think!) - [post w/ great pix, thanks Davey Doo!]
Why? Engine overheats and it has good belts, hoses, passes a pressure test and has no leaks.
Symptoms: Overheating, WP Pulley wobbles, water from the weep hole or the WP seal, overheating.
When? 50,000-100,000 or when it fails.

Camshaft Position Sensor (CMP) (http://www.rangerpowersports.com/forum/showthread.php?t=188596) diagram/parts list.
Why? It's a sensor, but the synchronizer turns your oil pump! Replace as a set if you can. New, never used since it has to mesh with the cam gear.
Symptoms: [95+ only]. Difficulty starting, no oil pressure, "chirping" from rear of engine, CEL (codes: ).
When? 100,000 or more, should inspect/replace BEFORE it fails.

[Link coming soon:] Timing Chain[/URL] - also see water pump since it has to come off and should be replaced.
Why? It it snaps, you could bend valves/pushrods or worse.
Symptoms: "trailer hitching" on decelleration, difficulty finding Top Dead Center.
When? 150,000 or when it fails the "slack test" in the manual (6* max).

"Painless" Distributor Installation! (http://www.rangerpowersports.com/forum/showthread.php?t=162051) - A Rogue Performance Exclusive!
Why? It it controls the ignition and drives the oil pump!
Symptoms: Difficultiy starting, rough idle that never goes away, engine turns and rockers move but the distributor doesn't spin.
When? 150,000 or when it fails the "wobble test".

kina of hard for me to vote on this i only got42000 miles on her
but would be nise to see the final out come for the future

first engine only lasted 30k.
because of me, lol


used engine,
water pump failure
then rad failure
heater core failure
i went ahead and did all hoses at that time.

i wish i would have dont the timing chain just for peace of mind.

some dis wobble, nothing that has been noticable mpg or perfromance.

115k on the truck now, orginal o2's

get ruffly 21-26 hwy
get ruffly 14-18 city
two core rad, pusher and puller fans 180 thermo, never over headed.

8mm wires and iriduim plugs past 20k (love them)
at 23k fuel filter was replaced, now 92k on it.

replace ment engine had lean bank 1 and bank 2. fixed with 19lbs injectors. stocks were maxed out acorrding to pcm codes.

now ruing a 2003 intake tube. much better looking but not sure if it flows more. (july 22 dyno run will tell.)

U/D pully past 30k only real problem i found is excessive idleing the battery gauge goes down and fluters a lot but yet it still makes 13.9 volts no matter what rpm or load.

original engine (as far as i know)- 106000 miles mostly highway or at least the last 19000
have only changed the plugs (twice thanks to aa)
new plug wires, k&n air filter, ud pulley
still have o2 sensors on my to do list but so far running 19/21 so im not to worried