P0305

[ace305]

I got P0305 misfire. I swapped coils with cylinder 3 and the misfire is not present. What could that mean? The plug look like it had some carbon on the plug but not the diode. Does it take some time for the misfire to come back? plugs are new, coils look to be original 2001.

thanks

 

[wmburns]

The misfire could be from:

• moisture in the spark plug well
• COP boot insulator
• carbon traces down the spark plug insulator
• bad spark plug including plug fouling.
• bad COP
• weak electrical connector

What many people don't realize is that IF there's spark escaping the boot insulator that if allowed to continue will CAUSE the boot insulator to fail. Once the insulation has broken down, then even if the original problem is resolved the misfire will continue.

I'm a big fan of starting an ignition tune up by just replacing the COP boot insulators. A full set of 8 is less $$ than a single new COP.

More Information for NGK 58901 $2.06 each (set of 8)
https://www.rockauto.com/en/moreinfo.php?pk=1596600&cc=1385636&jsn=439

 

[ace305]

The misfire could be from:

• moisture in the spark plug well
• COP boot insulator
• carbon traces down the spark plug insulator
• bad spark plug including plug fouling.
• bad COP
• weak electrical connector

What many people don't realize is that IF there's spark escaping the boot insulator that if allowed to continue will CAUSE the boot insulator to fail. Once the insulation has broken down, then even if the original problem is resolved the misfire will continue.

I'm a big fan of starting an ignition tune up by just replacing the COP boot insulators. A full set of 8 is less $$ than a single new COP.

More Information for NGK 58901 $2.06 each (set of 8)
https://www.rockauto.com/en/moreinfo.php?pk=1596600&cc=1385636&jsn=439

hey thanks. I inspected the suspect COP. the rubber looks ok. is this something you can't visually inspect?