Error codes and confusing situation
 

Hey i have a few questions first off i have a 2000 hyundai elantra with around 122k miles on it i recently started having a shakey motor, so i went to autozone and checked the error codes, i got a p0300 p0301 and p0304 code which i found out was a misfire of the system i checked on here and on other forums for what i can do, the misfire is the problem. I have recently replaced the plugs wires, fuel injectors, and fuel filter in the car, and it still misfires, i checked on here and it says that there is a vacum line is open i have been looking for it but i cant find which one can be. all i know is i rechecked the plugs and 1 and 4 has carbon tracking on it, and i checked for arching on the wires and nothing. and i know the injectors are working. so i dont know what else to do please help.. I appreciate any insight or queries to help me resolve this problem

RE: Error codes and confusing situation
 

You likely need a new coil pack. Cylinders 1 and 4 are misfiring, which are served by the same side of the coil pack. To test the coil:

2000 > G 2.0 DOHC > Engine Electrical System

MEASUREMENT OF THE PRIMARY COIL RESISTANCE

1.Measure the resistance between connector terminals 3 and 2 (the coils at the No.1 and No.4 cylinder sides) of the ignition coil, and between terminals 3 and 1 (the coils at the No.2 and No.3 cylinder sides).[/align]

http://www.hmaservice.com/data/Passe...G/V5EE035A.gif

MEASUREMENT OF THE SECONDARY COIL RESISTANCE[/align]

1.Measure the resistance between the high-voltage terminal for the No.1 and No.4 cylinders, and between the high-voltage terminals for the No.2 and No.3 cylinders.[/align]

Be sure, when measuring the resistance of the secondary coil, to disconnect the connector of the ignition coil.[/align]

http://www.hmaservice.com/data/Passe...G/V5EE035B.gif