Ok I've changed plugs,wires,rotor and cap. I have a S10 4.3 2000 I have pressure tested the pump got 66 pounds with the key on after the pump turned off pressure drop 20 pounds but after Istarted the engine I got 53 pounds and was very steady. Ok here is the problem when driving above 40mph. The truck has surge you can watch the tach move 300-500 rpms when the truck climbs any size incline I have check for engine codes right now there are none. Before I change the plugs I was getting a misfire code on the number 2 cylinder. Thank you in advance for any help.