Performed service diagnostic. No gas leak was detected at the furnace. Further inspection found that the odor in the home was coming from the stove top. An unlit burner for the stove had been left on. Performed AC cool check. Checked electrical, mechanical, safety, and performance of the system. The capacitor on the condenser unit was below value and at risk of failure. No other major issues were found. Options for repair were presented to customer and they chose to have the capacitor replaced today. Repair was completed. Electrical disconnect confirmed in and on. System was running at the time of departure.