I thought I better get back with feedback since I had so much advice from knowledgeable people. I had used regular fuel for the five years I owned the Lexus. I was going to throw a fit at Kendall Lexus anchorage about promising me that I could use regular when I bought the car. When I picked up my car after the new parts I talked to the mechanic. Very impressed with him. I didn't feel like he was tooting Kendall's horn, or his own dept. either. He said he wasn't sure it was regular that caused the ignition coil failure as well as the fuel igniter problems. I asked him how he would handle my dilemma. He said he'd use premium gas and that it would probably make a big difference in mpg also. I love my car and was going to sell and buy another similar but not Lexus car. So, that's why I didn't make a huge effort. What would it achieve? All they would do is try to sell me a new car. Would they go in to the computer to rearrange the settings? No, said the mechanic.