AARRGGHHH

My Mustang misfires badly when cold. Once the car gets up to operating temperature, the misfires stop. The original check engine code was lean air fuel mixture. After about a month of this, the misfires became a bit worse (although still only when cold), and a new code popped up: random misfires.

SO, now I have lean air fuel mixtures and random misfires. I took the vehicle to Tires Plus to have it diagnosed, they came up with replacing the coil, spark plug wires, and spark plugs. There are two concerns I have over this diagnosis:

1. It does not address the lean air fuel mixture.

2. I don't understand why an electrical problem like the coil, wires, and spark plugs would get better when the car is hot. I've never seen an electrical problem improve with heat, so I wonder if this is really a problem.

Hopefully some members here will have some insight on what should be fixed first. Also, I'm curious, what does it mean when the "random misfires" code is recorded, instead of recording "cylinder 1 misfire" "Cylinder 3 misfire" etc...

Thank you