My accord runs and drives great, but whenever it has been sitting for 4-5 hours when I start the car there is a white smoke billowing out of the tailpipe, and the motor runs rough. It lasts for around 3 or 4 minutes then stops, at which point the motor runs a lot better. Any help is greatly appriciated.

 

You need to replace the valve seals.

 

^^^That or you may have a small head gasket leak where the pressure in the cooling system continues to leak into the cylinder after you turn off the car. Are you replacing coolant? If not then it's probably your valve seals as mentioned. White smoke usually indicates coolant or water vapor in the exhaust. A grey/blue is usually oil, sometimes confused with white.

What does it smell like, burnt oil or does it have a sweet smell to it?

You could do a coolant pressure test to check for a coolant leak. There is no real test for valve guide leaks other than the burning oil on start up.

 

I thought head gasket also, not valve seals. I'm 90% sure its white smoke because I can only see it at night and not during the day. And if I drive the car, shut it down and restart it before the engine cools then it won't smoke any but once the engine cools it will.

 

If it's only at night (cooler) then it could just be water vapor/steam. Smoke will be visible anytime of day at any air temperature.

 

So are you saying that it just runs rough when the motor is warming up and I see water vapor

 

It's hard to determine what is wrong if it smokes at night and doesn't smoke during the day.

Have your coolant system pressure checked that way you can at least confirm or rule out the head gasket as an issue.