MAZDA B3000 ENGINE POOR MILEAGE

My Truck Is Having Serious Gas Mileage Problems And It Has Been Happening Ever Since I Got The Truck. It Has No Check Engine Light And The...

In The Last Week, My Mpg Has Gone From 20 To 10. When I Get Up To Between 45 To 55mph, It Starts Lurching, And If I Shift To Fifth, With...