2005 missing badly

[von dutchoven]

For the last couple of weeks my 2005 (240k) has been running a little rough but it seemed like a tune up would fix it. New plugs, oil and air clean but there was no change. No CEL. Then a few days ago it got worse and threw codes PO300 and PO301. Moved the number 1 coil pack to number number 2 and the code followed so I figured bad coil. I put a new one in and it ran much better for a day. Driving to work it started missing really bad. Had it towed home and this time when I pulled the codes it was PO300, PO301, and PO302. I looked a little closer and the wiring is toast. Would that make it misfire that bad? It was really bad.

I’m thinking about getting the Dave Barton repair loom at this point instead of trying to make my own

[Astro14]

Yes, bad wiring would be a cause. The wiring delivers the electricity, and the firing signal, to the coil. Bad wiring = intermittent spark.

[ocean 506]

Mr. Dutchoven,
I have installed the harness on two P2 cars. It was pretty easy to do. I see as of 1/11/24 they are on back order. Be patient, they are worth the wait.
Jon

[gary g]

IN the meanwhile you could use electrical tape or that liquid wire insulator stuff. Not a real solution but if it helps it would confirm the diagnosis.

[vtl]

When you install the coil, always use sand paper to clean the contact pad on the coil itself and on the valve cover where it touches the engine. Torque the bolt to the spec. This is the high voltage circuit's ground, the coil does not work properly without that ground and dies prematurely.