I am going away for vacation and am getting my mechanic buddy to go over my car with a fine tooth comb as my GMPP is running out on June of this year. I figured while he has the car (14 days) he might as well change the serpentine belt, water pump drive belt and a new fuel filter. As well, I am taking the transmission cooler lines to a hydraulic shop as they are leaking AGAIN. I want that problem corrected permanently. Is there any other preventative maintenance items I should deal with at the same time?? I have had my car since brand new and she now has 45k miles on her and other than oil changes (every 3000 miles), air filters and one coolant flush. Also I changed the front rotors when I put on ceramic pads to get rid of the constant brake dust issues. I was thinking of maybe having the plugs changed?? Any suggestions or comments would be appreciated. I notice sometimes when I start her in the morning she runs a little rough while idling.

Clean up the throttle body, the MAF, the IAC sensor. GXP venom would be one of the best people to ask about what to have checked.

Spark plugs. Getting dealer to spring for them would be cool. Could be the rough start idle. Wouldn't think so @ 40k but yours is a year older. Mine'* occasionally rough at startup. But its seldom, and doesn't last long. These aluminum block really warm quickly.

Ya, check the maf screen for sure. I got some litle stuff in there, dont know how it passed the air filter. But it did. Might have not quite seated it once. I use to have it off alot playing with the Nitrous jetting. Can always have him do a scan just to make sure all is well. I have OnStar which is nice. The service talks to the PCM and does a monthly scan of everything and sends the report to my email.

Thanks guys, much appreciated. I have ONSTAR as well and at the moment it shows no problems. Getting the dealer to change the plugs would be great but unlikely. The rough idle is intermittent so they would have to reproduce it.