1991 Chevy Camaro injecters?

Starting up it idles high and sounds rough. Going down the road it acts like it's not getting enough gas, but I do smell gas sometimes. It spits and spudders when I try totake off too fast or if I kick it down. But sometimes it runs smooth as hell. I changed the fuel filter and it's not reading codes. Could it still be the MAP sensor?

Thanks,
Colonel