No power on acceleration

Okay, when I hit the gas to accelerate such as in getting on an expressway, this vehicle struggles to get to sixty mph (especially going uphill). The check engine light is on so I went and checked the code it said multiple misfires. I put in all new spark plugs and all knew ignition coils. The engine runs much better, but it still feels like the engine works too hard to get to speed. Check engine light is still on. Code says EVAP leak. I got a new gas cap, no change. Went under the vehicle and saw two hoses disconnected. I am not sure what they are connected to. Looks like some sort of plastic housing under the drivers seat. Anyway, I reconnected them but it still feels like the engine works too hard, as if it is pulling a heavy load. I want to say it's a transmission issue because the engine runs just fine now. I checked the transmission fluid and the level and color is good. Could it be the filter or a sensor going bad? I would think being a V8, this vehicle would "jump" a little when I hit the gas. It does not stall or hesitate at all it just will not accelerate equal to my hitting the gas pedal. Revs up high and changes gears, but takes a long time to get to gear change speed even if I floor it (briefly).