I have a 95 chevy beretta 2.2 liter. Engine has a miss after the speed has settled out. Not there under accel. New plugs,wires,had no effect. Swapped out coils no change. Timing light shows steady on all 4 plug wires. No engine fault codes. How can I eliminate the injectors or the ecm without replacing them. Any other suggestions or tests to eliminate suspect bad part.

 

doesnt sound like an injector problem might check the egr valve by disconnecting the valve and driving it to see if the miss goes away, if its vacum operated just remove the vacum line, if its electronic egr suggest trying to clean the valve first as they can get gummed up with carbon and cause sticking movement of the egr pintle. driving the vehilce with the egr disconnected will likely cause the check engine light to come on and store a code for the egr system, and may cause engine to ping a little so just drive it enough to see if that is causing the problem.
after checking egr and you have found it isnt the problem you may have to take it to a shop for diagnossis as they will have the equipment to pinpoint the problem whether it be an ecm or sensor, etc.