I have a 2000 Silverado V6 with about 50,000 miles on it. About a month or two ago it started hesitating every now and then when I would pull out somewhere and hit the gas hard. Then one day as I was driving to my parents' house about 50 miles away, it would not go over 45 mph. If I tried to accelerate anymore it would sputter a little and go even slower. I changed the fuel filter and it worked fine for a week (save for the occasional hesitating like it was going to kill when I pulled out from a stop) until I drive to my parents' again today and it does the same thing where I can't go over 40-45 mph. I try to show my dad what it's doing about 2 hours later when he gets home and it is running fine again. Anyone know what the heck the problem could be? Thanks in advance.

Could not hurt to try and dump some injector cleaner into the tank as well as some isopropyl. My Silverado was doing something similar to me a while back and the isopropyl solved the problem. After 50,000 miles maybe a tune up would be a good idea as well. Plugs, wires, considering it is a 6 cyl; cap and rotor.