P0300 Code "Cylinder misfire"

Post by **jimmy57** » 19 Dec 2019, 22:18

Do you ever feel it misfire or run rough? If you can find when it does it and drive it to get the misfire to happen a lot then you will get a cylinder specific code. The p0300 is the acknowledgement of misfire but the ECM has not seen the misfire on enough consecutive revolutions to identify the exact cylinder. If it misfires a lot then it IDs the cylinder number and you save a lot of work.

Post by **vtl** » 19 Dec 2019, 22:20

If I remember correctly, B5244S does not have a cylinder-specific misfire code.

Mr. Detail · Post by **Mr. Detail** » 20 Dec 2019, 05:58

Just a follow up guys. This morning I turned the car over and the "CHECK ENGINE" light went out. I did not reset it when it was on yesterday. Now what? replace the coils anyway? Maybe what Chrism stated about the plugs I bought would be a cheaper start.

MERRY CHRISTMAS to all!!

Post by **vtl** » 20 Dec 2019, 06:04

You have to have a spare ignition coil anyways...

One thing I forgot to mention: the little bolt that holds the coil to the valve cover is actually making a high-voltage ground point. Every time you remove the coil, you better clean the contact on the coil and on the valve cover. And tighten the bolt appropriately, don't leave it loose. Along with a mismatching spark plug this is the most common reason of why ignition coil dies prematurely.

But yours can be replaced just because they are very old

Post by **abscate** » 20 Dec 2019, 06:08

That’s a generic misfire code with the cylinder not specified. If it is running well, and you can’t feel any misfires, it might be a very subtle occasional one.

I would run it without clearing codes to see if you can get the cylinder identified with a P030x code, where x will be the cylinder in question.

I just had a thread in the P80 where a new out of box Volvo plug went on week after install, to a hot only misfire condition.

Holy crap - I completely ghosted the posters upthread who covered this already..

Apologies

Mr. Detail · Post by **Mr. Detail** » 20 Dec 2019, 07:18

chrism, as you can see by his post here spoke of a single copper electrode for my B5244S (NGK BKR6ES).
Is it possible that they don't make one of those for this application?
I just got this message back from a NGK guy: "Looking at our cataloging system we do not offer a copper core spark plug for this application. What we offer is BKR6EQUA stock number 5767. This is an OE equivalent spark plug and is nickle cored. This is a multi ground electrode spark plug. This has 4 ground electrodes."

Supergrunged · Post by **Supergrunged** » 22 Dec 2019, 15:31

vtl wrote: 19 Dec 2019, 18:42 I bought a replacement wire harness for the ignition coils and VVT solenoids. Just need to splice some wires...

I just used 3M Super 88, as it's rated for high temps as high as the engine bay is gonna get. Just wrap the wires so there's no copper showing