I am looking at getting a 2002 F250 5.4L V8. I was wondering if anyone has had any problems with them. Also what kinda gas milage and tow capasity. I appreciate any help!

 

I have a '97 F150 with only the 4.6L engine and it tows my 24' 7,000 lb. race car trailer fairly decently but it loses speed on uphill grades. The newer 5.4L engine should definitely be a better towing engine in a newer F250. Gas mileage will depend a lot on what you tow and what kind of terrain you have to drive on and the rear gears. I've got 3.55's in mine and it takes me about 1/4 tank to go a round trip to the strip which is only 56 miles or so, but then again the same engine is running hard with a lot of throttle to pull the rig I have.
You can probably get the towing capacity and specs from the Ford truck website. Hope the truck you're looking at has the towing package as this makes it easier to hook up trailer brakes with the adapter cable you can get from Ford.
BTW, the 5.4L engine is not 351 c.i., it's more like a 330 c.i. engine as the 4.6 is only 281 ci.