My Honda 2005 Honda Accord 2.4 liter, 213000

I can run around town forever and it runs great but when I get on the highway and drive for a little more than 20 minutes it starts misfiring and stalling really really bad. If I totally let up on the gas and just accelerate at an extremely slow rate it clears u.... but as soon as I try to accelerate a little faster it will stall out or misfire.... once this begins it will do it at all speeds.... if I stop for a little while it will clear up but begins again much sooner....

Nope if I'm just driving around town stopping and starting.... stopping at a store Etc everything runs great..

Any idea what it is or where to start

 

Get the trouble codes read and post the actual code numbers.