Under load, the demand for air, fuel, and spark are higher,
so aged components in these systems may not operate
optimally. Here's what I'd be considering, in order so as to
minimize expenses but get to a solution quickly:

What are the age and miles on the air filter and fuel
filter? If either are over two years old, replace them. Any
improvement?

How old is the oxygen sensor? Report back.

Is this a carbureted Accord? Carburetor may need thorough
cleaning.

If fuel injected, add a bottle of Chevron Techron fuel
injector/system cleaner when the fuel tank is next low and
just before a fillup.

How old and how many miles on the ignition wires, plugs,
distributor cap, and rotor? Have you tested the ignition
wires recently for resistance? All should be less than about
15k ohms. Use only OEM parts for these items.

Check the PCV valve. With the engine running, wrap a cloth
around its supply tube, squeeze the tube closed, listen for
a click, indicating the valve is operating. Consider
cleaning with WD-40 or PB Blaster. If it's the original one,
regardless of the test outcome, replace it.

Top off and purge the cooling system. Use the free online
manual for your Accord at www.autozone.com for directions.
Follow the directions exactly to get a thorough purge.

Consider a new oxygen sensor. Should be under $45 for an OEM
one at https://www.automedicsupply.com/ .

Review www.tegger.com/hondafaq , under running/starting
problems, for reinforcement on doing many of the above items
and further ideas on troubleshooting.

Things I suspect strongest: air filter, fuel filter,
carburetor fouled, oxygen sensor, ignition wires and plugs,
about equally. There may be some overlap in what's causing
the problem.

Do you have any revving problems when the car is sitting at
a stoplight and idling?