P0300 Code "Cylinder misfire"

Mr. Detail · Post by **Mr. Detail** » 19 Dec 2019, 11:05

Any opinions as to why I am getting this check engine light code especially after I have already changed out my spark plugs this past summer?
The plugs have only 2k miles on them and I bought the OE Volvo ones with the funky 3 pronged electrodes.

Post by **vtl** » 19 Dec 2019, 11:18

Ignition coils.

ignatz · Post by **ignatz** » 19 Dec 2019, 12:56

I had a broken wire.

Post by **vtl** » 19 Dec 2019, 13:51

Yeah, check wire loom too. If you see anything disintegrated - replace it with a fresh loom right on spot. If any wire touches the metal - it may cause a misfire.

Mr. Detail · Post by **Mr. Detail** » 19 Dec 2019, 13:55

vtl, what does the "wire loom" look like? Is that the main cable bunch?
Also can I cheap this out by not having to buy Bosch coils at $40 a piece?

Post by **vtl** » 19 Dec 2019, 14:02

This: https://www.amazon.com/gp/product/B00KW9RHYG

Buy one coil, swap it with every coil one by one until a bad coil found. You can probably judge which cylinder is bad by looking at spark plugs.

Post by **volvolugnut** » 19 Dec 2019, 18:17

Try to get the high temperature wire loom. IPD has it is some sizes. Try to get at least 300F rating. The cheap, general duty stuff degrades under the hood and especially on top of the head.
volvolugnut

Post by **vtl** » 19 Dec 2019, 18:42

I bought a replacement wire harness for the ignition coils and VVT solenoids. Just need to splice some wires...

Post by **chrism** » 19 Dec 2019, 20:44

Mr. Detail wrote: ↑19 Dec 2019, 11:05 The plugs have only 2k miles on them and I bought the OE Volvo ones with the funky 3 pronged electrodes.

Personally I'm not a big fan of those sort of plugs. If swapping coil(s) out doesn't fix it then you might consider a set of plain old copper core single electrodes like NGK BKR6ES. I've had great service from those and the price is right.

https://www.ngk.com/product.aspx?zpid=9345

Post by **vtl** » 19 Dec 2019, 21:10

chrism wrote: ↑19 Dec 2019, 20:44Personally I'm not a big fan of those sort of plugs.

His plug are stock for B5244S. Made by Denso.