does my 2001 F 150 have a factory engine heater of any sort?

Do you mean a block heater? That is an option, you would have to look up your vehicles purchase options, ie build sheet. You can also crawl under and look for the block heater plug, which takes the place of one of the freeze plugs. It would have a cord running up under the bumper with a cap on it. Again it's an option, not a default piece of equipment.

Unless your truck was sold in a northern state where it gets really cold I doubt it came with one. Aftermarket heaters are available. http://www.amazon.com/Kats-1160-300-Watt-Handi-Heat- Magnetic/dp/B000I8YOR4/ref=sr_1_1? ie=UTF8&qid=1449123028&sr=8-1&keywords=engine+heaters

Hi guys. Good info. Especially if your truck is a diesel. I don't know if block heaters are really even needed on gasoline engines.. unless you live where it get's 40° below

If it were a diesel it may have one however in 01 half ton trucks ford did not offer a diesel engine option, now if the truck was bought in MT,ND,SD,CO,KA,WY,OR,and ID it may have been an option on gasoline engines, however gas does not gel up as like diesel does, the most u would need in the fridges temps for a gas engine would be a battery blanket unless of course u have watery gas then that will lead to a world of head aches

Block heaters on gasoline vehicles basically serves to keep the engine oil from turning into a viscus blob. One needs well below Zero temps (like -30) for that to happen.