Front cylinder seemed to be firing just a little late giving a much louder exhaust note and less power. Inspection of vacuum hoses from crankcase vent to backing plate behind air cleaner showed a major crack at the vent. The hose came off in my hand. Replacement cost was about $5 so I replaced them both. Engine now idles a little high. Have to clear the codes before crusing. Will disconnecting the battery for a few minutes clear the codes as it does on most cars?