My 2000 honda accord pulses between 1000 and 2000 rpms when it idles. When I drive down the interstate it kind of jerks when I let off the gas. Egr valve is not old. Any ideas what is wrong

Air in the cooling system? Open the bleeder bolt and fill the radiator with coolant, until it comes out the bleeder bolt.

Might be time for a tune up if it has been awhile. Also clean your injectors and replace fuel filter.

Could even be something as simple as a vacuum leak as I have seen these symptoms caused from that before. Really though, it's difficult to diagnose something like this without actually being able to check it out.

Would the map sensor have anything to do with the problem

No.

Fluctuating idle rpm is usually caused by vacuum leaks (too much air), which the ECM constantly tries to adjust for--hence, the fluctuations as the engine "seeks" a level. Check for vacuum leaks--examine hoses, Fast Idle Thermo Valve (ensure valve seat is tight), and Idle Air Control Valve (IACV).