If yours is a turbo, the PTC valve is on the air intake close to the turbo inlet. The best way to clean it out is to remove the pipe from the car, not easy. The PTC valve has an electrical connection making it easier to identify. Note where the other vacuum lines are and make sure they are tight and not cracked when putting things back together.

I left the PTC in the pipe when I cleaned it. Lots of throttle body cleaner and a very small screwdriver to ream out the deposits.

When putting the air pipe back in the car, fit the turbo end on first and tighten loosly until the pipe is in place, then torque it down hard. The last thing you want is a loose pipe fitting falling off a week later.

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