Rough idle - 1996 Suburban

Hello,
My 1996 Vortech 350 Suburban is getting engine codes 300 and 1153. There is a rough idle at stoplights and above 2500 rpm it is smooth. New platinum plugs, wires, rotor, cap, and intake air sensor.

Any help would be appreciated!

chevy's dont like the platinum plugs , but that prob. isn't it. go ac delco... I've tried them all... most are coming with 100k iridium plugs($10 per) There is a site alldata that has a fee $ 24, that is real informative. your codes are o2 sensor(insufficient switching pre converter right bank) and engine misfire

Po300 missfire, 1153 injector number 3 problem
This engine does use platinum plugs.
Run some good injector cleaner in the fuel tank. You might have picked up some dirt chnage the fuel filter also. After a tank or 2 of gas with injector cleaner in it and you still have the problem you will need to check the enjector