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!

Edited May 13, 20178 yr by jeromeleo

Was there oil of the end of the plug wires when you changed the plugs?

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

What brand plugs, what brand wires?

What was the coil replaced? Subaru coils almost never fail.

Was this work done for preventative maintenance or to fix an existing problem?

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?

Subaru or NGK wires and plugs.  Stock Coil.

Dealer wanted your money.

 

Plugs and wires are a common maintenance replacement, but if it was running fine before it's likely they didn't need to be changed.

 

Three things:

1:what kind of NGK plugs? Owners manual lists the part number for the proper plug for that engine. There should also be a sticker under the hood that says which plug should be used as well as the proper gap for the plugs. Using the wrong plugs can cause misfires. Setting the gap incorrectly can cause misfires.

 

2: Get NGK or Subaru OE plug wires. These engines don't tolerate cheap plug wires.

 

3: Put the original coil back on.

 

 

Washer seat spark plugs generally will turn about 3/4 turn after the washer makes first contact. Once the washer crushes the plug will get alot harder to turn, that's when you stop turning. Something like 15-18ft lbs will be the final torque. I've always done it by feel.

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

Get a used stock coil. Aftermarket are garbage. 

 

GD