The engine does not hold idle (and seems to be running rough).
This old Duratec has VACUUM activated secondaries in the LIM (unlike the electrically operated system I am more familiar with). The spring in the actuator seems to hold the secondaries OPEN (and I haven't seen it moving, but not sure if in neutral the RPM get high enough before the rev limiter kicks in).
Also, there is a strange sound (resonance?) coming from the intake. I can stop the noise by opening up the air filter box.
Where should I start with troubleshooting the idle?
Thanks.
This old Duratec has VACUUM activated secondaries in the LIM (unlike the electrically operated system I am more familiar with). The spring in the actuator seems to hold the secondaries OPEN (and I haven't seen it moving, but not sure if in neutral the RPM get high enough before the rev limiter kicks in).
Also, there is a strange sound (resonance?) coming from the intake. I can stop the noise by opening up the air filter box.
Where should I start with troubleshooting the idle?
Thanks.