Did they share codes with you.

 

They said the computer showed that it was carboned up and restricting the throttle body operation. Something like that. I was dead asleep when I heard this from the service advisor.
The Evap purge valve issue threw a P0442 code.

 

Any self-respecting dealer owes it to themselves to propose the most costly solution first. To familiarize with the action, literally first hit using your thread title:

What Is A Fuel Induction Service And Is It Really Needed?

Do you really need to get your fuel induction service done at the dealership? Here are some reasons why you might want to do or skip one.

mechanicbase.com

The comments add some more info for reference.

Knowing nothing of either your interest or ability in DIY, here's a well illustrated example of TB cleaning, the parts and supplies for which would be only a fraction of having that service performed. An online supplier like RockAuto might show a listing for a rebuild kit, or just the gaskets and any other wear parts inside. There won't be many if any. And lacking any description of what the "fuel system cleaning" part of the service includes, be mindful it may end up nothing more than the same bottle of Techron dumped in just the same as you can do on your own. For $12.

CliffNotes:: I'd start a routine of Techron to observe gradual improvements. And ANY retail car parts place will let you borrow an OBD-II reader to get any codes. I didn't look it up, but the EVAP Purge thing can simply be one of the outcomes of 'topping off' when filling. And we all know NEVER top-off when filling.

Loop back what you decided on, and the results eh.

 

I'd change the 30 dollar valve myself - easy peasy, buy some throttle body cleaner ( not carb cleaner) its a easy cleaning when you remove it completely, buy some CRC cleaner

Amazon.com: CRC® Gasoline 1-Tank Power Renew® 15 Fl Oz : Automotive

Buy CRC® Gasoline 1-Tank Power Renew® 15 Fl Oz: Fuel Additives - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

I'm away from home at work, so I don't have access to me tools, garage etc. No DIY for the time being.

I did get everything done, and the car drives dramatically better. I'd noticed a lumpiness at idle over the last few weeks, and that's completely gone. I sure won't say it faster, but it's certainly much smoother than it was. I wish I could say what aspect of the service caused the improvement, but it's certainly there.

I can't say I'm unhappy with the outlay, as I have a better running car out of it, and it's established a better baseline for what it should be. I always felt the 3.6 should be smoother then it was at idle, but now, after todays service, I'm completely satisfied.

 

Had my XTS in the shop today, as the check engine light came on. Evaporative emissions issue. Anyhow, the dealer recommended a throttle body/ fuel system cleaning for $300 cdn. Call it $225 USD. The car is coming up on 60k miles.
is this worth doing? The idle has seemed a bit rougher of late. Related? Or do I run a few cans of GM fuel system cleaner?

Cleaning the throttle is a very easy. I replaced the throttle body on my 2009 STS and it took maybe 1/2 hour.

 

For the OP, good to hear you got fair exchange for $$$ spent. Did they let on about what all they did?

 

I also get the feeling the actual fix was something besides cleaning the throttle body. Who knows, but at least they returned the car running great.