The ICV (Idle Control Valve) can be cleaned once removed.
But, it should *not* cause the vehicle to backfire. It sounds like you're dealing with a large vacuum leak. Here are some things that you should have a look at.
After checking for any obvious vacuum leaks around the top of the motor, the
Crank Case Ventilation System should be next on the list. Make sure to check for leaks at the CCV on the rear of the intake manifold (requires removal of the intake manifold if you need to replace it). Also, the gasket behind the Throttle Body. Below I've added diagrams of the systems and their associated hoses.
Shown here is the Vanos to Crank Case Ventilation. The CCV located on the back of the intake manifold is located behind #7 (it is not numbered in this diagram). Number 5 is located underneath the Intake Maniforld.
This pipe is aluminum and has internal valves to allow forced air into the cylinder heads
Diagram of the Air Pump and it's associated hoses.