Customer stated that furnace was making a loud grinding noise. I cycled system in heat and found inducer motor fan blade making contact with assembly housing during ignition sequence. Adjusted mounting plate which corrected the issue. If inducer fan continues to slip and make contact with housing, inducer assembly will need to be replaced. Provided estimate for repair. Performed clean and check on gas furnace, cycled system in medium and high heat stages, conducted combustion analysis, measured temperature rise, inspected burner assembly, cleaned flame sensor and condensate trap, tested and inspected all electrical components and blower motor assembly, tested t-stat operations, changed filter and humidifier pad that customer provided. Everything is otherwise operating normally at this time. Customer paid cash.