I've got a 2004 Grand Prix GT. 3.8L, V6 engine. Approximately 30,600 miles.

Today while stopped at a stoplight, the RPMs jumped from around 700 to about 1200 and then quickly went back to 700 again.

I'm not the most car savvy, so I wondered: Is this something I should be worried about? From what I've read in other posts, it could be the spark plugs. (I had significant problems last fall with this vehicle: fuel injectors had to be srubbed and one replaced, new catalytic converter installed, spark plug replaced, etc.)