Bill Brown

Looking for some insight.. my truck started to hesitate coming from a stop but then smooths out when your on the throttle and today I noticed while putting gas in it that there were a few drips coming from the filler neck somewhere. Would my truck be sucking in air from this crack/hole and causing the slight hesitation? Also my heat doesn't work really. I barely have heat on the lowest setting and if I turn it on full blast it then begins blowing cooler air. I have replaced the thermostat and noticed the lower radiator hose is cool to the touch even after driving it for an hour. There's no fluid on the passenger floorboard so I doubt it's the heater core. Could my circulation be screwed up somewhere? The water pump seems to be working since I see no leakage or anything. I bought the truck from a car dealer and been having problems with getting them to fix everything come to find out they went out of business last week. I'm on limited income so if I can fix it myself I will just need some general guidance. Thanks for your help