That low idle could be due to the throttle body needing a reset. Definitely try doing the idle relearn and make sure there aren’t any vacuum leaks. If it still persists, the idle air control valve could be the culprit.
So my dad’s 2010 Suzuki Swift speedo is way off—like, 55 mph is showing around 20! Tach, temp, and fuel gauges are chill though. Swapped the speed sensor, still no luck. Any clue what’s going on? Wiring issue? Gauge cluster? I'm stumped!