This truck model is very unreliable. I am replacing something constantly, the truck manages to leak oil, water, even dot 3 fluid for the transmission. I think the check engine light being on constantly comes standard from the factory. The people responsible for designing and producing this truck in 2001 can be thanked for the incredible rise in Toyota, and other foreign truck sales in the US since its introduction into the market due to such notorious unreliability.
I have a 2001 F-150 4.2L 6-cyl. My dad bought it in 2002 with about 15,000 miles on it. He ran it for 12 years loaded with all of his work equipment, which was a pretty heavy load. When I got it about 2 months ago it had 285,000 miles on it. As of now it has almost 289,000 miles on it and I'm confident I can get it to 350,000 miles easy. Original engine and tranny. The only things that have been replaced is the rotors, oil pump, drive shaft, and basic maintenance. Last month I ran it into a guide rail and other than a broken headlight and a bent bumper it was fine. I rely on this truck to get me to work and college on a daily basis. Very sturdy and reliable.
Low maintenance, definetly built Ford tough, pretty good mpg for an older truck.
This is by far the best vehicle I have ever owned. I have over 220,000 miles on it and it just keeps on going strong. Minimal maintenance costs. Well built truck. Replaced the clutch and slave cylinder, brake pads and tires. Thats it. Awesome truck.