engine has a surge type of idle during cold weather temps wich trips the engine service light. It idles fine during warm weather and the light goes out. I was told it is a blocked egr tube but I can't find the egr on this model of the 5.3
poor idle during cold outdoor temps on 2002 Chevrolet Silverado 1500
This happened on my truck as well. I work in a repair shop and what we found was that the cold weather was actually shrinking the intake gaskets allowing the engine to suck in too much air. Replacing those gaskets took care of the problem. This happened last winter and since repair we haven't had any problems this cold winter. (I'm from MN as well)
A blocked EGR tube should not cause a cold idle surge. Is that the only code stored? The EGR valve should be located at the right front of the engine. The best technicians all use shop manuals in their work. Perhaps you should invest in one. It will help you define the fault codes and diagnose the EGR system.
i would have a shop scan the OBD2 computer to pull the trouble codes. these codes will lead you down the right path of repair. Without knowing these trouble codes, this issue could be related to many different components. but sounds like it is in the ignition system.