Never had problem until after change air filter. Rpm normal at 1.5 rpm while driving but goes up to 2 and back down recently.
My car has 283000 miles.
My car has an automatic transmission.
You may have a vacuum line off. Removing the air filter on many cars involves disconnecting and reconnecting some hoses, or at the very least pushing some out of the way. I would revisit the air filter and make sure there are no small hoses hinging there not connected. It can be surprising how much affect some of these small hoses can have. If you can’t pin it down, you can have it checked out by contacting YourMechanic. They can send a technician to your home or office to check out your Pontiac and let you know what it will take to fix it.