P0301 1st cylinder misfire

[Sublimenalmssage]

I just got my tacoma fully maintenance and 2 weeks later the check engine light came on, I got it decoded and P0301 came out saying I had a 1st cylinder misfire. When my truck idles its a very deep rumble. I have a feeling it could be the fuel injector or a clogged valve, but I was wondering if I can get some tips or advice in what to look for and what to do about it.

[johnecon2001]

Pull your plugs and give them a look. Check for fouling, hot burn or just incorrect gap.

Or take the truck back to the place that gave you the maintenance and complain.

[Sublimenalmssage]

So my buddy and I looked at the plugs and they were completely fine, they were the densos, We did a compression test and cylinder 1 is at about 125 psi, 5 to 10 lower then the other 3. We don't know where to go from there, I put in gumout high mileage and started filling up with premium gas to start being more cautious about the valve gunk build up, any other suggestions?

[toytec]

swap coils to a diffrent cylinder to see if the problem moves.

[Sublimenalmssage]

So we switched the coils and reset the check engine light and when it turned back on it still read P0301, I Was thinking of looking into the injectors or to clean the valve do you have any other suggestions of what it may be?