I have just swapped a frankenmotor into a 98 forester. The franken motor is a ej25d block and ej22e heads. The forester originally had an ej25d.
This engine came from a 95 legacy, from which the intake and heads are original to. The engine had this horrible misfire before swapping. I assumed maybe the misfire could have been an anomale in the ecu or harness of the 95, but it is still present in the 98 forester.
The #2 injector has been replaced, no cure. The #2 injector drops out at idle, and under load, the #1 injector drops out as well.
I thought i had read something about a bad signal from the IAC will cause this. Upon startup, the engine sems to run smooth until it idles down to the point the IAC closes, then misfires.
So i swapped the intake harnesses. The car now has the forester's original harness on teh intake. So my problem is not the intake. It must be an individual component on the intake itself. i had to swap over the purge control solenoid and the knock sensor to match the harness I have not attempted to swap the coil. I loathe to change the IAC with the little hoses of death under the intake (i don't want tp pull the intake-again!)
HAs anyone had this trouble before, swap or not, and what should be my troubleshooting route: to reiterate, i have swapped over the forester's original engine harness, knock sensor, and purge control solenoid. All of the forester's original components are known working order before the swap. I can rule out any ecu or harness as the problem.