Sounds like a cylinder isn't firing

Finally got the car started and it sound like one of the cylinders on the driver side isn't firing. I can hear it in the exhaust and feel it when I put my hand against the exhaust.

I changed all the plugs, since it had been a long time. The motor is new and has less than 10 miles on it. Should I do a compression test?

I just found the problem. Unplugged fuel injector. You guys make me think outside the box