Engine Light and Hold light flashing

[zero_cool09]

So I got an OBD2 reader. Code is p0300 just like I thought. Going to be replacing the first cyclinder spark plug as when I pulled all the plugs out that seemed to be the one that looked worse for wear, there was build up of oil I'm guessing because it wasn't firing.

I did the misting of the coil and wires trick, and didn't get any arcing just to check that they were not the issue. Although I know thats not a for sure way of knowing. I just didn't feel comfortable with pulling the spark plug wires off the coil while it was running.

[zero_cool09]

The spark plug wires have been replaced. I talked to the guy I bought it off who is a mechanic and he believes there is a vacuum leak. But the only code I ever got was p0300 and my engine light and hold light still are flashing.

Any ideas?