Thanks. It looks like I unfastened that bolt at some point in the process.

The CEL started to flash, and the car had a rough idle. I pulled the codes and got P0303. To diagnose the problem, I switched the coils for the 1st and 3rd cylinder and cleared the codes. Drove it down the street, CEL flashed again. The code was now P0301. (P0303 was gone.) I thought I was pretty cl...