my 280ZX failed the emissions test in NC and the guy was good enough to give me some advice, since the car sat too much it was blowing too much junk out when it did get to run, so I drove it every day for two weeks and tried to go at least five miles everytime I cranked it ... on the day I was taking it back to be retested I filled it up with premium ( no additives ) and took it out on the interstate, got it up to as fast as I dared go ( yeah, I'm not suggesting you drive as fast as I did cuz it would have been time to convince the judge to let me keep a license ) and ran it long enough to get it good and hot, drove it straight to the shop and pulled right up to the door, got out and told them not to shut it off just hook it right up to the machine and it came through with flying colors ... so it probably just needs to clear its throat, if you already drive it a good distance every day that might not do the trick for you, but if you don't it's worth a try