I have a Honda Civic (LX) 2000 (automatic) which is under 45,000 miles. I have a very interesting situation. Over the last several years, I have had this occurring almost once a year during summer. When the car has been running for a while (not always for very long. At times even after 30 minutes or so) and moving slow or idling in traffic, the engine suddenly starts revving and moves forward even when the breaks are applied. Then I would stop the car and shift to park mode and switch off the engine. If I start the car again right away or too soon, it will start and will continue to rev and shift will get locked in the Park mode. If I stop the engine and wait until the car cools down for about 30 minutes or more, then the car will not rev when started and the shift will move as normal and car will run again as nothing has happened. When this happens, the temp gauge seems to be in the normal range but the rpm goes high. As I had noted, this almost happens only once a year during summer. I am so confused why this is happening because this car runs so smoothly. I have done several long trips and nothing has happened. Any advice or insights are greatly appreciated. Thank you in advance for your kindness in helping with this matter.

Several thoughts:

. Reset the ECM, by pulling the 7.5A BACKUP Fuse in the under-hood fuse box or by disconnecting the negative battery cable for 15 seconds.

. Check for codes.

. Clean the Idle Air Control Valve (IACV):

https://www.askmehelpdesk.com/cars-t...ml#post1054149

. Test/replace the Ignition Control Module (ICM)--be sure to apply heat-transfer silicone grease to the back of the ICM.

. See if the link below offers any insight:

https://www.askmehelpdesk.com/cars-t...tml#post258005

. Change the automatic transmission fluid, preferably with a synthetic product. Engines, ECMs, and transmissions work together. If the transmission has not been well cared for, it may be contributing to of causing the weird problem. Your transmission's temperature may be soaring, when the problem develops. Synthetic ATF, because of its higher coefficient of heat, allows transmissions to run much cooler.

. When stopped in traffic for a while, it's better to shift into Neutral than leave the transmission in Drive.

Thank you so much for your valuable insights. I will try some of these and see whether it will take care of this wired problem. Appreciated your kind advice and insights. Thanks again!