Just last night i reflashed my 02 ls8 with the xcal 2 and a 93 octane program i got from steeda. Well after about 15 minutes of driving i got CEL. I pulled the 3 codes and they came out to be p0171, p0174, and p1000. Well i cleared the codes last night and on my way to work this morning again after about 15 minutes it came back and i pulled the same codes. The car sounds great and runs really well, i can feel the difference with the tune. Any idea what may have happened and/or what those codes are saying. Thank you in advance.

try the link below

http://www.canobd2.com/support/DTC_lookup.asp

Thank you for that post, that is exactly what i needed. Now according to that it thinks it is running too lean, any ideas why it is giving me this or what i can do about it.

Lean conditions can be caused by a multitude of problems. But since this popped up with your new tune, it's a safe bet that it is caused by the tune. I would contact who you bought it from and tell them the problem. They can email you a new tune. They may want some sort of datalog to see just where the problem is however.