drove 400 miles today. About 10 miles from home i get on it for the 1st time on the trip. boost went to about 24( it is set to 26), started knocking. i backed out of it, 02 was at 718 with 6.8 knock at only 73mph. It has been fine so don't know where this came from. My fuel setting is still correct and the alky lite was green..