Unlike some have said don't start with shit like ignition components. You said it was running smooth and a 2012. This could be perfectly normal operation. It's called a high idle and used to help get the catalytic converters fired up. The only thing you need to do is hook up a scan tool. You can get bluetooth ones for $20. There may be history/pending/current codes even with the MIL off. If you don't do this first you're wasting your time and money. If you have a vacuum leak it might not have a P0171 or P0174 code yet. So then you look at Long Term Fuel Trims for both banks. They should stabilize at 0% +/- 10%. If they are >+10% you likely have a vacuum leak causing a idle hunt. That or your throttle body is dirty/not adapted. Clean your throttle body and clear codes even if their aren't any, turn key off for ten seconds, turn key on and do not touch anything for ten seconds, fully depress accelerator a couple times, start engine and let idle for a minute or 2. Take on a drive and see if any codes pop up. Do not just start replacing shit.