Stalling, hesitation, flooding, high idle

Hey this is my first foroum ever used but I really need some assistance. I have a 1984 chevy cavalier type 10, with 140,000 miles

it starts at idliling, It is really high then smooths out but then gets high again, its stalling is very constant at stop signs and if I have to sit at a train stop, I will push on the gas but it hesitates, if it stalls out It wont start for 10min and smells flooded, if I stop to get gas and shut of the engine as soon as I fill it up it wont start until it sits for about 10min.
also there is a weird clanging in the engine at neutral or in reverse
so I have had the computer replaced, it was costly and didnt do anything, I have checked for vacuum leaks, and I checked the plugs these were weird, 2 of the 4 seemed normal one was filled with oil above the spark plug, and the other 2 had very wide gaps so I replaced them all.
any suggestions would be very appreciated :D