Hello,

I own a 2003 Honda Accord 4-cyc,auto trans with 38k miles. I've notice my car idles rough when stopped in drive. I'll be at a stop light and the engine idles rough. The tac is around 800 rpms. When I step on the gas to go, the rough idle goes away. When I put it in park, the rough idle goes away????

Does anyone know what this problem could be???

Thanks,
Sheryl S.

 

Rough like vibrations? Or does it surge faster & slower instead of a steady RPM?

If it vibrates, maybe it's the vacuum-operated front engine mount. Wanna check it out yourself? It's front & center, labeled #9 in the picture below.

There's a vacuum line #16, #17, & it somehow connects over to a solenoid valve in the box labeled E-3. (My 2003 was a manual tranny, didn't have the vacuum-operated mount, so I don't know exactly where that solenoid valve is located.)

Get the car warmed up, have someone in the car, with the engine running. Put it in Drive or Reverse & hold the brake. Unplug the electrical connection to that solenoid valve. That SHOULD make it real rough. If not, then the mount isn't working properly. Let us know what happens, & then someone can figure out what to check next.