I've had my check engine light on solid for awhile and took it in for a diagnostic. The code came up MAF sensor had gone bad so I replaced it, they cleared the code out and then the light came on again two days later. I went back for another reading and I got the following:

P0301 - Cylinder 1 Misfire
P0411 - Secondary air injection system incorrect flow
P0172 - System too rich bank 1

My plugs and wires are fairly new (less than a year), and I reseated the wires and checked the run to the coil (that was replaced last year too), and the wires are all in perfect shape, no cracks or wire showing.

What could be causing these errors?

 

I have encountered a similar problem. My Sister-in-law's car has not been idling right. When I pulled codes it came up with the same first two you had. I thought it was just bad plugs. After I changed them the light came back on. I no longer have a cylinder 1 misfire but still get the P4011. I am going to check for a leak in the hoses going to the air pump. I do not know if it is the same but I will let you know if I learn anything.