Hello everyone,

My family's Volvo 240 engine idling is inconsistent, specially at the stop sign when the car has to proceed, the engine hesitates. However, when the car accelerates it picks up RPM and power. I have done the following work on the engine and still am having problem with start up, rough idling, and running rich.
Replaced air idle valve
Replaced pressure regulator
Replaced throttle position switch
Cleaned the throttle body
Replaced fuel pump and fuel filter
Replaced Oxygen sensor
Installed new Bosch copper spark plugs
Ignition coil is good
Air mass meter is good
Warm or cold, the idling is rough and oscillating. I very much appreciate for any ideas or tips you may have to share.

Thank you,
Habib