Hello again,
It is no problem at all, and I have all day so it dosen't matter if you are a mechanic or not. But I do need to understand what is going so I can help you. We will get this figured out. Okay, that's good. Direct Trouble Code(DTC) P0304 is indeed a misfire in cylinder #4. Misfires are categorized into two types, type A misfire, and Type B misfire. It's been a while since I was going threw factory training with Honda so I can't recall what the criteria is exactly for a misfire being a Type A misfire, but I do remember that if your Malfunction Indicator Lamp(MIL)a.k.a."check engine" light illuminates and flashes, it is a Type A misfire. This type of misfire is serious and is called a catalyst damaging event.
I personally own a supercharged mustang gt and three years ago I had a problem with my Mass Airflow sensor(MAF), which tells the PCM the amount of air entering the engine, a very critical sensor for engine longevity. My engine blew up, that is to say I blew a hole threw the top of my #4 piston, bent and fractured the connecting rod, and lost all compression in that cylinder. My MIL came on and was flashing. This is an example of a catalyst damaging event.
If you could please do me a favor and go to the links down below.
https://www.2carpros.com/articles/symptoms-of-low-compression
https://www.2carpros.com/articles/the-reasons-for-low-compression
https://www.2carpros.com/articles/how-to-test-engine-compression
I know you guys have a done a compression test, but if you could please humor me and re check it for me that would be great. Please get back to me with what you guys find out.
Thanks,
Alex
2CarPros
Saturday, March 16th, 2019 AT 8:19 PM