The EGR and normal operation send burnt/spent gasses back through that portion of the intake. Carbon buildup is normal. Excess amounts of it restrict the normal flow of air; causing the engine to 'stumble'. If you want to be safe, get sensor-safe throttle body cleaner. If you are really ballsy, remove the part (if you find a lot of carbon)... and do not use brushes or scrub the stuff off! Let it dry completely before starting the car to make sure.
I'm gonna look this process up in the shop manual...
If you leave it on the car, do the job with the car running. The car will bog down a bit as the chems are burnt and passed, just stop spraying.
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