Experiencing rough idle for few seconds after car has been stopped . usually overnight in garage. After idle evens out the car performs well and restarts with no rough idle. Next day experience same symptoms.

Mechanic has checked for leakage from injectors and of course has problem duplicating.

120K miles 2001 9-3 convertible - garage kept southeast usa .
Problem has occured past 2-3 months last major maintenance was replacement of motor mounts.

Any hints we can share with our service manager?

 

any codes pop up? could be something simple like a filter...

 

No codes does not idle rough long enough to throw codes. Just in 2 weeks ago mechanich did vacum test . did replace o-rings in throttle body. now idles rough only when completely cooled down (4-5 hours) .
any other saab mechanics in columbia , sc area we are willing to try another shop.
or suggestion on less expensive parts to try to replace?