Idle problem

Yes, I know. The 1000th time for a post about idling problems. My 92 5.0 will idle fine except when I am sitting to long at a stop light(another words , when I`m in gear to long). All of a sudden idle goes choppy to the point that I have to feather the gas while holding the brake. This is what has been done so far. New plugs, Clean K/N filter,new cap and rotor, clean maf sensor, tps checked and adjusted to .99 with volt meter, idle solinoid cleaned. I have not touched salt and pepper yet as just about every plastic part I touch on this car breaks due to age. Any suggestions??