My 96 gmc sierra idle issue fixed after two years of hell

just some info for you obs vortec guys out there.... ive had a bad idle after full warm up for nearly two years now.. had a ase shop work on it to no avail.. replace every sensor as I could afford to, new fuel system from tank to injector tips, new ignition coil, dizzy, plugs, wires the works.. still missed as soon as warm.. did compressions checks countless times always great compression cold and hot.. so I was like the heck with it I guess it just wants a ls swap in its near future.. so one day an old man said check the valves again..but when its hot and idling full temp.. so I said what the heck and did.. three of them were just a flippin hair tight and on full temp would slightly leak causing the major miss like I had a dang huge cam but without the power!! plus my fuel mileage went from 21-23 on hwy to 9-10 it sucked. sorry this is so long but I wanted to share in case yal had the same issues and couldn't figure it out.. man I miss old cars