My 89 Civic Si is misfiring at >3500 rpm.
This happens standing still or driving.

The car is a Solo STS car, that is, mostly stock.
No recent modifications.

The problem started a week ago. It stalled and then would not run for more than 30 seconds if it would start at all.
After replacing the following items, it starts, it idles and it runs reliably at <3500 RPM.
- Dist. Cap
- Rotor
- Plug Wires
- Plugs
Today I replaced a couple things because I had them around, did not improve high RPM misfire:
- Ignition coil
- Oxygen sensor
During the troubleshooting process I have checked most of the sensors and controls in the manual and they were fine.
I have not driven the car around enough since replacing these parts to generate codes. So I may do that now.
Any ideas of the most likely problem would be appreciated.

 

its either your timing or your distributor.

get a timing light and check your timing (remember to jump the service terminal)
if your timing is good....
take your dizzy off, check how smooth it rotates. it should spin easy. if not, you need to replace the bearing or get a new dizzy

if both of those check out, try borrowing a known good dizzy to retest