Sound the the fuel pedal

It may be a CVT gearbox failure. From what I know about these cars, that sounds like that.

Thank you for your answer,do you how much it cost to fix it?.regards

This is probably an idle condition, and you should have noticed it upon start (vehicle in P)... Erratic idle (loping up and down) is a re-occurring problem on this generation of Honda...and can usually be addressed with the following. Make sure that the cooling system is filled and burped to perfection....and the vehicle warms up to an acceptable operating temperature. If these conditions are met (it should idle at about 500 to 700 RPMs), and the loping should subside. If she continues to idle erratically, you must insure that the timing is correct, especially at the distributor (they can be bumped forward and cause the problem), but if you have no distributor (coil packs) forget about it. The usual culprit is the IAC or Air Idle Control Valve, which appears in many forms on the Honda/Acura intake manifolds. They can usually be removed and cleaned (they get really gummed up with cooling system depoits)...then reinstalled (make sure you burp and top off the coolant). Lastly, all Honda have an air idle adjuster screw, right on the top of the throttle body. You can tell if it has been moved, because they just have a standard screw driver head, and can be difficult to turn (easy to leave marks on the aluminum). Now turn that baby counter clockwise until the erratic idle simmers down...that might be all she needs! Lastly, I would like to know the specifics on this one to answer with certainty...is it a 4cly Accord or V6? Anyway, Good Luck...my fellow Accord owner.

Oh and obviously the condition disappears when you put the Accord in D...because that loads the motor, and the idle can't change without actually moving the vehicle (keep your foot on the brake...LOL)