Volvo: 1997 960 volvo, fuel economy, filter air

Question
i have a 1997 960 volvo that cranks up  and runs rough  without much power but when it gets on the road it changes to good power; any ideas what may be the problem?
             thanks

Answer
Please clarify...you mean when it idles in your driveway it sounds like it's struggling, but when you get out on the road, it perks up and does its thing?  Does it have trouble cranking up (hard start)?  Does it still get its average fuel economy?  Any start-stop traffic problems (run rough/overheat at red lights)?  Do you change oil/filter, air filter at reasonable intervals?  Spark plugs, wires in good condition?  Alternator doing its job?
J. Davila