89 ka24e bad cylinder HELP

[celica3sgte94]

i have a 89 249sx with a ka24e my 4cylinder isnt firing the engien shaks ALOT. i changed the plugs, wires, cap, rotor and just right now i changed my injector (from junkyard thou tried with 2 injectors) but still no good what is making my 4th not fire???? everytime i shift gears i hear a poping noise from my exhaust and my engine shaks alot please help i want this problem solve ASAP

[180fan]

check the resistance across the injectors. post the resistance value. next is check to make sure your injector is getting a signal in the first place.