need help with 95 grand am

95 grand am only running on 2 cylinders we have no codes and parts we have tried are : ecm , coils , ignition modual , knock sensor , plugs , crank sensor. the compression is around 135 lbs per cylinder checked the timing chain it is on the money , did a ohm test on the coils and they were within specs , also did ohms on injectors they are within specs , cylinders 1 and 3 are dead 2 and 4 are firing fine i even pulled the plugs and switched them thinking maybe 2 plugs were bad made no difference. also pulled the plugs and layed them on the engine to check spark and 1 and 3 still not firing i forgot to mention it is a 2.3 quad 4 any ideas where to go next i am out of ideas thanks.