OK here it goes my 94 5.0 started surging again and stops when it warms up. Awhile back it was doing this then stopped and idled normal for two weeks and started again today it will surge and almost die also when coming to a stop RPMS will drop to 500 then shoot back up to normal.ive checked vacuum lines checked maf sensor, spark plugs/wires i refilled yesterday with 89 octane could it be something with the fuel system