Limp Mode Issues?

Im having the same problem with my 03 and it has a brand new battery im sure you will keep having problems because the battery isn't it. I am replacing the wiring harness that leads to my throttle body today and which anyone with this particular problem should do the same.

Ya I put my scanner on it last week and yesterday I replaced the lead to the throttle body and it runs like a champ.

The subject light first appeared in November 2006. Battery Cables were adjusted and tightened and diagnostic codes were reset. All was fine until this week (14 December 2007) when same light reappeared. GMC service techs now say it is the throttle body that needs to be replaced at a cost of $750. Is this a reasonable solution and cost for the job? Thank you.