Rough idle on 2005 9-5 Arc sedan

[Ohioan]

We just purchased a 2005 9-5 Arc sedan with 72000 miles.

It runs O.K., but the idle is a bit rough. The RPM will increase for a second, decrease for a second, and then steady out. Four seconds later the RPM will increase for a second, decrease for a second, and then steady out. Over and over. It seems worse when it first starts.

No error codes have (yet) been displayed on the alphanumeric display.

Any ideas on what to check first?

[XLR99]

Wow that car isn't even broken in yet! Out of curiosity, where in OH are you?

Seems that throttle bodies are a common issue with the 9-5. FWIW mine does the same thing intermittently, but has never thrown a CEL.
Other things to look at: CPS, vacuum leaks, clean the throttle body and mass airflow sensor. I've done all of the above on my car, which improved things to the point where the idle issue shows up maybe once a month. I'm fine with that; if it starts popping a CEL, I'll replace the TB.

[Ohioan]

Appreciate the advice. Will look into those things.

[XLR99]

No problem, it's quite likely you'll be able to get it fixed with no more than a cost of the CRC MAF cleaner spray.
Also be sure to do basic service stuff like fuel filter, air filter, plugs, etc.
Between the reference pages Wulf put on this site, asking questions, and a few other sites like FixMySaab: Home Page, you can easily get good intel on how to do your own maintenance and repairs.