03, 6mt coupe. went out to defrost snow. ran the car for 20 minutes in the driveway. when I got in it to leave i noticed it running low RPM's under 500. thought maybe nothing and drove to the store and back. when I get home it's still doing it. i can feel the motor running rough, but no engine codes . WTF.. checked the motor, oil is good. any ideas?

 

Are you sure it is below 500? Right at 500 is where my idle is. I doubt you can tell a difference from 10-20 rpms. Take a picture of it.

 

Do you have any mods like intake, headers,
You should try a search...you will probably find a solution.

if all else fales, try to reset the ecu.

 

did a search no results yet. I know that outside temps & air temps can affect sensors. this is the first really cold I'v had since buying the car. there was 6 inches of snow on it. the rpms re floating at the first line above 0 it's never been that low, it's usually at the second line. also no engine mods yet.

 

Clean your throttle body if you have not done so already. Change the air-filter too.

 

Here's a good thread on that:

https://g35driver.com/forums/intake-...gine-idle.html

 

while you're cleaning your TB/filter make sure you clean the MAF too.