[error codes 301,302 , 303, 304]

Ok.  Thanks... I'll replace plugs, but the coil is gone

[error codes 301,302 , 303, 304]

Hi, Thanks for the response.  I was told by Subaru they all needed to be changed. $550!!!! SO I decided to do it myself.  I used Car Quest wires, not sure of the coil, and NGK plugs. In the meantime I cleaned the Mass Air flow sensor , but that did nothing.

 

Should I get new ... better wires?

[error codes 301,302 , 303, 304]

No, they were dry. I'm wondering if I should reinstall the plugs with a torque wrench.  I did not do that on original installation.  But when the first problem occurred, I firmed up the four connections to the coil and that seemed to fix the problem.  I'm wondering if something is wrong at that end.  I just don't know how to check or where to start

[error codes 301,302 , 303, 304]

Put in new plugs, new wires and new coil on daughters 2009 Impreza.  Car worked fine for two days and then stated stalling.  Readjusted connection to coil and that seemed to fix the problem,. But no! now it bucks, dies, etc.  Ran scan for the problem and it says all four are misfiring.  Where do I go from here. Also, new transmission went in less than a year ago. Replaced air filter when I did plugs and coils.Trust no shops and Subaru will kill me with price.  What should I look for now?

 

Help!