My child has high functioning autism but feels an urge to make weird sounds that he can not stop?

Yes....: That is part of self stimming behavior common in autism spectrum disorder. Have you talked to or seen an autism specialist? Have you trued diet changes? Has he seen a neurologist (?Tic issue). Allergies can sometimes contribute.

Possibilities are: Compulsion, vocal tic or stereotypy, that probably increases when he's anxious. Usually it can be treated with Clonidine or long-acting guanfacine, but it sometimes requires neuroleptics. If his cognitive ability is in the "average" range or above & his receptive & expressive language abilities are adequate, cognitive-behavioral therapy or specific habit-reversal therapy may help.

One idea: Asperger's / high function autism can run with Tourette's. I have a physician colleague who has this and is easily managed by a specific medication. Best wishes.