Can someone help me determine if there is a certified CNG mechanic in my area? I am 15 miles from Modesto and 25 miles from Merced. My son-in-law has loaned me his older Cavalier CNG-convertible-to-regular-gas (two tanks) to test drive and decide if I want to buy it from him. If there is no one to keep it running, I will have to turn him down.