2002 Sierra misfire only when cold?

[Tyler]

Hello everyone, nice site you got here. I have an odd question for you. My captain at work (Kettering Fire) has a 2002 GMC Sierra with 80,XXX miles on it. He replaced the plugs and wires about 6 months ago, along with filters. He says that just about this time every year his truck does the exact same thing. It will randomly misfire every now and then until it warms up. After its warm it runs perfectly fine. And it only does it in cold weather. Does anyone have any clue on what in the world could cause this??? Thanks a lot!

 

[bigdisneydaddy]

If its noticeably misfiring it should have a code stored. thats where you want to start.