I have a 1993 Civic 5 speed with a D15B7 (NON v-tec) motor with 95,000 miles on it
The car is operated in a relatively cool area (Vancouver, B.C.)
Under load (pedal to the metal) is stumbles until 4000 RPM and then is smooth as silk
(I notice it more in the lower gears)
The car has NEVER not started, never stalled, nor ever let me down
It idles perfectly (both hot and cold)

This is what I have done to the car (so far)...
New plugs and plug wires (NGK)
Distributor cap and rotor
Checked timing (but did not adjust it)
Re-soldered the Main Relay (one of the smaller solder connections WAS cracked)
Gas filter
Air filter
I have used fuel injector cleaner a few times in the past month or two

I have not checked NOR replaced the PCV valve, the TPS, MAP sensor, nor ECU

To be honest, it isn't getting any worse and I could live with it as it is

I would genuinely appreciate any suggestions 'you' may have.

Thanks.
Gordon

Really make sure that the plug wires are seated on the plugs, this has happened to me a couple times on civics.

Here's what I would do:

. Replace the Ignition Control Module and coil:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-4.html#post265896

. Clean Idle Air Control Valve and throttle body.
. Check vacuum hoses, particularly to MAP Sensor.
. Perform K-Test on ECM.

TXGREASEMONKEY I was hoping you might post a response. You seem to know lots about Honda Civics. So, THANKS.

I have a KNOWN good distributor for my car which I will swap into the car (maybe tonight - depending when I get off work). I'll let you know.
Gordon

I have a 1993 Civic 5 speed with a D15B7 (NON v-tec) motor with 95,000 miles on it
The car is operated in a relatively cool area (Vancouver, B.C.)
Under load (pedal to the metal) is stumbles until 4000 RPM and then is smooth as silk
(I notice it more in the lower gears)
The car has NEVER not started, never stalled, nor ever let me down
It idles perfectly (both hot and cold)

This is what I have done to the car (so far)...
new plugs and plug wires (NGK)
Distributor cap and rotor
checked timing (but did not adjust it)
re-soldered the Main Relay (one of the smaller solder connections WAS cracked)
gas filter
air filter
I have used fuel injector cleaner a few times in the past month or two

I have not checked NOR replaced the PCV valve, the TPS, MAP sensor, nor ECU

To be honest, it isn't getting any worse and I could live with it as it is

I would genuinely appreciate any suggestions 'you' may have.

Thanks.
Gordon
I am wondering if you ever figured this problem out? I have a 90 hatch that is pretty much doing the same things you have described. Your explanation is worded so much better than I have been able to do here . Any feedback would be greatly appreciated