Hi Guys:
Fuel pressure may be the problem too. Many suggest change the fuel pump. My car had trouble starting too and would idle rough. I changed my camshaft sensors and crank sensor, fuel filter, and eccentric sensor only to find out it was a fuel rail pressure problem. In your case, it could be a loose injector connection to the fuel rail. The retainer clips may not have the injector fully secured in place. The o-rings get worn or damaged, especially if the fuel rail and injectors have been removed recently. Removing the fuel rail unseating the o-rings to inspect will require new o-rings upper & lower to re-seat properly and pressurize properly. If there is failure at the fuel rail on re-installation, misfire codes tend to be multiple cylinder and possible individual cylinder misfire codes. Once you inspect the retainer clips, and replace the o-rings, don't forget to clear the OBD fault codes before re-starting the engine.
Regards,
HPIracer