Reader Question When I start my 2002 Hyundai Elantra car my RPM shoot to about 3000 then slowly keep rising. Also, when I drove it my car, for the lack of a better term, drove itself. I would let off the gas and it would maintain speed with a little decrease in speed. I know it needs work just hoping I could have some info before I go in there.
It may be a little vague but I have very limited knowledge and wish to learn as much as I can.
I hope for a little enlightenment on the subject.
Thanks for your time.
A few things come to mind and I would check if you were at my shop –
1. Look and listen for a vacuum leak under the hood. With the engine running, open the hood and look for a rubber or plastic hose or hose connection that might have gotten knocked loose or broken off. Listen for a hissing noise that will be caused by this vacuum leak
2. Clean the throttle body and idle motor. Any mechanic should be able to do this for you, or at least inspect it to see if it needs cleaning. Periodic cleaning should be part of general maintenance anyway and will provide for smooth idling.
3. Check the throttle linkage – have someone work the gas pedal inside the car (ENGINE OFF) while you look under the hood and watch the linkage move on the top of the engine. Make sure nothing is in the way or interfering with the linkage
4. Read your on board computer codes and test a few sensors like the TPS – Throttle Position Sensor to see if they are working correctly. You did not mention that the check engine light was coming on, so I would probably suspect a problem with 1-3 first before I started replacing sensors.