Hello. My car has gone around 95,000 miles. It's been having idling issues on cold start. It occurs after the car sat for a while. I would start the car and it would start idling high. It would go around 900 RPM and gradually increase it. Then it would stay at that high RPM for some time. Also there is another issue that might be connected to the first one. When I shift into gears, the car would jump back and forth when I let go off the brake pedal. Do you have any idea what could be the cause of these issues? Thanks.
When the vehicle surges such as what you have described and has a high idle, they are generally related. A few different items can cause this fault such as the MAF sensor, a vacuum leak, a throttle body fault, or a failing transmission. If you want to have a professional take a look at this, a certified technician, such as one from YourMechanic, will have no trouble diagnosing your high idle issue, and performing any required repairs.