A few more basics to check or do:

-- Dump a bottle of Chevron Techron fuel system cleaner into
the car's near empty fuel tank. Fill with gas.

-- Check the ignition timing.

-- A bad O2 sensor will not necessarily set off a CEL on a
1994 Honda (pre-OBD2). Since the problem occurs after
warmup, that makes me especially suspicious of the O2
sensor. https://www.automedicsupply.com/ has the best
prices I've seen for OEM O2 sensors: About $69 altogether. I
have used them. Good, prompt service. Maybe not a bad
investment for a car this old.

-- Purge cooling system thoroughly of air. Follow the
manual's instructions. Getting the fan to come on may take
as much as 40 minutes of idling. If various ECM sensors
aren't cooled properly, then this may cause erratic
behavior.

Are all the ignition parts (plugs, wires, distributor etc.)
OEM?

<jrlomas@sgintl.com> wrote
>I have a Honda Civic LX 1994 that stumbles on acceleration.
>It seems
> to be worse when it is warm. It feels like only one of
> the cylinders
> misfires while accelerating, making the car lack power and
> vibrate, and
> once the RPMS get high enough, at around 3000RPMS, the
> misfiring
> dissapears. Nonetheless, it is a combination of the
> engine load versus
> the RPMs, I can get it to stuble at any given RPM setting,
> if I press
> on the throttle pedal too hard. Here are the parts I have
> now replaced:
>
> Entire distributor, including the cap and rotor.
> Spark Plug Wires
> Spark Plugs
> Fuel Pump and fuel strainer
> Fuel Filter
> Fuel Rail
> All 4 Injectors
> Fuel Regulator
> Air filter
>
> I have checked the TPS with a multimeter, 0.5V at closed
> throttle and
> 4.5V at full throttle smooth transition in between.
> I have tested the MAP sensor with a hand vacumm gauge and
> a multimeter,
> sensor is all nominal but here is the chart if anyone
> cares to look at
> it:
> 0psi 2.80V
> 5psi 2.34V
> 10psi 1.86V
> 15psi 1.39V
> 20psi 0.96V
> 25psi 0.52V
> I have tested the fuel pressure, pressure is normal.
> I have tested the O2 sensor with a multimeter and propane
> torch. Again
> it seems to be normal. I have also disconnected it from
> the car and
> driven it without the lambda sensor, still the car behaves
> the same and
> stumbles.
> I have checked the timing with a timing light, and the
> timing is right
> on according to specification.
> The ECM reports no trouble codes. The ECM reports no
> "Check Engine"
> light while driving, although the car stumbles wildly.
> I am running out of ideas... can anyone think of anything
> else I should
> check or that could possibly be the reason for the car
> stumbling.
>
> - JR
>