P30x Codes and Cylinders

I’ve been having trouble finding a solid answer to P30x codes, cylinders, and firing orders. For example, on a 6-cylinder engine with a P304 code saying a cylinder #4 misfire, I’ve seen information that it’s the 4th cylinder in the firing order, which may not actually be cylinder #4. So if the firing order is 1-4-2-5-3-6, I would think that it’s really cylinder #5 to investigate because it’s the 4th cylinder in the firing order. But I see people in YouTube videos going straight for cylinder #4 (understandably because that’s what the code says) and not considering the firing order. Can anyone shed any light on this for me?

P304 indicates cylinder #4, not the 4th cylinder in the firing order. I may be old fashioned, but I believe you tube is good for watching the Ed Sullivan show, not so good for getting accurate info about car repair.


Thank you!

Information like below was throwing me off when it talked about the code digits “correspond to the cylinder number in the engine’s firing order”. I don’t know if they are saying it correctly and it’s just the way I’m interpreting the info, but it had me thinking I needed to know the firing order to use the code and track down the actual cylinder. I’ll go by the code digit telling me which cylinder it is and then just making sure I know which cylinder is that digit.


The last two digits in the misfire code will tell you which cylinder or cylinders are misfiring. The digits correspond to the cylinder number in the engine’s firing order

The last 5 words in that paragraph simply shouldn’t be there.

Perfect. Thanks again!

Do you know for certain which is the number one cylinder for that V6? If not, post the make/model/year/engine for your vehicle. Usually the number one cylinder is closest to the timing chain/belt, but that might not always be the case.

Thanks for responding. Yep, I’m all set now. The vehicle in particular was a Ford Windstar 2000 3.8 v6. Standing in front of the engine, looking at the car:
with firing order 1-4-2-5-3-6.

That’s why I was confused when I saw the bad info talking about the P30x digit being the cylinder in the firing order and not the cylinder #. I didn’t know if I should be looking at #4 or #5, but now I know it’s #4 like the P304 code says.

Here’s some trivia: On V -shape engines it might seem like there’s two cylinders (e.g. 1 & 4 ) nearest the timing chain(belt); but if you look carefully one is in front of the other. The connecting rods for those two cylinders share the same journal on the crankshaft, but they can’t share the exact same location. They are side by side, so one cylinder has to be slightly in front of the other. That’s the way it works on my Ford 302 V8 anyway.

Technical mistakes made in automobile repair manuals, websites, are pretty common in my experience. With talking about anything complicated it’s easy to write the prose, but difficult to get it totally correct. Ever tried to explain to someone how to drive to where you live? It seems like it should be easy, but when you try to do it, not so much. At least the mistake wasn’t made in instructions for operating a nuclear power plant … lol …