CEL ON, took into shop....ROUGH IDLE

[blackjack]

Alright, well this started a few months ago and it has yet to be fixed. I have a 1998 BMW 318ti with about 100,000 miles on it. I love this car and have had no problems until a bit ago. Anyways, I live in Wisconsin and it gets kind of cold up here, so I started my car in the morning (it was like -2 F out) and my idle was really really rough. I didn't think anything of it because it was so cold, but it has been happening ever since then. My check engine light didn't go on until about a month after this started. I took it in to the shop and they ran some fuel injection system cleaner through my car to fix it. It didn't work. They told me the computer said the cat was damaged, but I should be fine for 6 months yet, they told me like 3 of the 4 cylinders were misfiring.

Okay, still don't have it fixed. They told me I need new fuel injectors. The thing is, the car has a really rough idle for about a minute, and then once I start driving and it gets warmed up it's totally fine! Sometimes it doesn't start unless I give it a little gas. Think its just the cold??? I'm debating just waiting until it gets warmer to see if that fixes it.

Oh, I forgot, when I bought the car the CEL light would turn on once in awhile (once a month maybe) and then turn off after a few days or so. I never thought anything of it, but now I'm thinking maybe that had something to do with it.

Anyways, what are your suggestions or possible problems?