Lately, every few days, my 2002 Honda Accord V6 will act up. I start my car, it turns over right away, but the idle is very rough and varys from around 300 to 500 RPM, which is very rough and on the verge of shutting off. If i give it any throttle, it will rev ip but then it dies, i start it again and it does this over and over. The problem gets better and the RPM goes up little by little and goes away after a minute or two. It seems to to do when the engine is warm, it has never done it on a cold start. It stumps me because it only does it once ever couple days and it never has given me a dash light. Any help?

 

Likely your oxygen sensors are failing. Pull the connectors from the sensors when its doin it and see if it goes away. Yes, it will throw a code. No big deal, just see if the issue subsides.

Maybe need new spark plugs.