my 03 ranger, 2.9L. jerking, hesitating. i replace MAF 3 times, spark plugs, wires, and gas filter. when i unplug the MAF connection the jerking improve 10% also i could drive it a few miles only & when I plug back the MAF, the engine will start shaking/ jerking and will stall in less then a minute if i don't put my foot on the gas paddle. any idea? help please....