Does anyone know if there is a rule for vehicles that require a muffler or large trucks that are obnoxiously loud when driving down the street. There is someone in my neighborhood that I would like to ask to fix their vehicle, but wasn't sure if there were any rules that are to be followed?

sorry no rules, just listen to the loud Harleys on the road, they get away with it.

Your township should have Noise and Nuisance ordinances. Document and file a complaint with the township garnering the support of your neighbors if possible.