Sputtering while maintaining speed and accelerating

The first thing I noticed was my fuel mileage dropping. After two weeks of that it started running really rough after an hour and a half or so of driving. It slowly has been taking less time for it to start having the issue. It will start cutting out while train to maintain speed, during acceleration it gets worse. Occasionally I’ll smell fuel when this happens. I’ve changed plugs, wires, complete distributor, fuel pump, fuel filter, map sensor, O2 sensor and nothing has seemed to work. While changing the distributor, I found that the coil had previously been replaced but whoever changed it did not mount it correctly, they just zip tied it to a radiator hose. I resolved that issue while I was there. I’m more of a parts changer than a mechanic so I’m not sure where to go from here. I have has a couple people suggest that it could be a cracked head or blown head gasket but it’s not getting and water in the oil or oil in water and I have not noticed it smoking, but it only happens when I’m driving and I’m usually in semi congested traffic so I’m not watching my mirrors for smoke as much as I am traffic. Short drives don’t seem to have any issues, Any ideas?