when ignition is turned on engine idle is rough and car clunks surges but goes away at hinger rpm then reappears at deceleration then car turns off but turns on again no problem besides rough idle extra effort to brake surging bouncing at start up

When I first started the car,it was blowing steam out. When the steam stopped gun the gas several times and it blows sparks out. But still it just won't run. Can't get it above 2000 rpms. Let off the gas and it just quits. Fuel pump relay good,fuel pump is pumping gas. It gets mighty strong when trying to start it.