Mercury no start sometimes?

I have a 1993 mercury Tracer 1.9 stationwagon and bought as a work car for what i paid for it couldnt pass it up. BUT now that i got some of the bugs worked out, new wires coil valve cover casket and some others. Now every so often it dont want to start untill today it eventually started. fuel pump is working, resistance is normal on injectors 14-15 ohms, put a broomstick to each injector and they are ticking away like normal (have not checked spark yet, i knew i forgot something) when i purchased it i pulled the plugs and they looked new so i didnt change them BUT i did change #1 plug because it had been siezed in there good and because of that previous owner didnt change thinking it was going to break, so i changed #1 plug with the same type it was today that i learned that not all plugs are correctly gapped from manufact each one was .015-.020 off. Another issue is when the vehicle is running and idle if i step on it have throttle it wants to spit and sputter out but if i gently give it gas its ok.Please any help or thoughts ?

 

Fuel filter might be a good place to start. Also I would consider putting a pressure guage on to see what pressure you are getting out of the pump; just running doesn't mean it is puttting out sufficient pressure.