2011 chevy malibu. 3 days ago on my way to work my car would hit about 2500 rpms and drop then go back 2500 and drop continously. I stopped turned it off and it ran fine. now I’ve noticed when taking off from a stop it’s a jerking/quick (only once not multiple times) kind of go. It used to be very smooth. occasionally the rpm problem will return but less severe. any help/advice?