took out the thermostat,put the plugs back In,and drove it about 3 miles,now It feels like It's running on 3 cylinders at a stop sign,but clears up when I take off,got back home,and the coolant Is gurgling Into the overflow tank

2001 Durango 5.9 Magnum 99 Durango 5.9 Magnum Parting out 99 Durango 5.9,99 Ram 1500 and 98 Ram 1500 5.9 WANTED.Ram Truck,Durango/Dakota parts and parts trucks!!PM Me. GO BUCKS!!!! Go GATORS!!!!