I would replace the CKP sensor & then take it to the dealer to scan. There is a relearning produre that you should do. If you are going to pay them the $80 to hook it up. You should just have the do the relearn it. The ckp sensor is a common thing on these. I think the part goes for around $70 too. Try gmpartsdirect.com too it might be cheaper then. The wife car kept dying & I could not wait any longer for the part. good luck.
John