The only problems I have had with my truck is the bolt on stuff. You know, like water pumps, starters, alternators, radiators. The engine and trans. are both original. No problems with them.
If I was you, I would change over to synthetic oil, if you haven't already, and change it every 5000 miles. Run 10W-30. Change the air filter about every 30,000 miles. Fuel filter about every 7000 miles. Tune it up at 125,000 miles. Leave the engine alone. If you have one of those cheap plastic radiators, you will have to change it about every 100,000 miles. They are shit, but they are easy to change.
Oh, and get used to people saying, when are you going to get rid of that thing?