sounds like the ect sensor may be failing. that would be the temp sensor on the water pump. to test temp sensor, 4th Gen LT1 F-body Tech Articles

some tests for opti 4th Gen LT1 F-body Tech Articles

https://camaroforums.com/forum/lt1-l...m-check-74882/

 

Hook a scan tool up to it that reads live data and show us the results. It would be extremely helpful to see your fuel trim and your 02 sensor voltages before the misfire starts and during the misfire.

Fuel quality could also be an issue. Did you fill up before this started or anything like that?


..... this is one of those times where i wish ignition scopes were more affordable.