So about three weeks ago, I was headed to the gym and I used my spare key to start the car. The car began to stall which I thought was weird because it wouldn’t stall before even when I used the spare. So I grabbed the original key and the car started but when it idled, the car would shake and go below 1 RPM. So after cleaning the battery of its corrosion, changing the spark plugs, and getting a oil change, the car would still go below 1 RPM while idling.
Any ideas what the problem can be?