I have a97 ford f150 4.2 v6 new battery new starter alternator is good and when I turn the key it don't do anything but barley move like something is stuck.by the way it's a standard. What could it b

Check Battery Terminal Wires & Grounds to frame from engine block and battery to frame. As a precaution pull all spark plugs & turn engine over after marking all plug wire locations. This is to make sure the engine is not Hydro-locked. The 4.2L V-6 engines have factory issues with mostly the intake gaskets but head gaskets can always be a issue too. When they fail, can or will eventually leak coolant into a cylinder and causes the hydro-lock or crankcase to become saturated with coolant. While trying to crank the engine it is possible to bend or break a rod and or a piston. The 1997 to early 2000's and up had these issues. 1997 being the worst only while 1998 ford had solved the issue for the most part but still can fail and 1999 Ford tried again only to make them worse then the 1998 model gaskets but a little better then the 1997 models so they went back to the 1998 design for 2000 and up and improved them every year after but the use of plastic for engine gaskets are the ultimate down fail of the gasket material and none are 100% effective, But 1997 and 1999 were the worse of these (Intake) gaskets used.