Running on three cylinders

[(Yoshi)]

Hey my engine is running on only three cylinders and so far I have basicly done a tune up on it like plugs cap rotor fuel filter oil change except for pcv valve and wires cuz the wires were good. If I start the engine and let it idle and I pull the first spark plug nothing happens, but when I pull the other three the engine bogs down. I checked to see if I could hear ticking from the fuel injector and I could then I was going to take the injector out but one of the screws stripped so Im going to check it after I get one of those bits that will take out a screw as long as it still has a head.

Any how any ideas?

ThanksAdiosJosh