My 2010 prius had been giving low mpg since the last three months. It has now 145 K miles.when I bought it a year ago, it had 134K on it. I haven't changed the spark plugs, do they have any effect on low mpg? , my mpg is about 39 now,but was 42_45 before. Another question: what are the symptoms for the spark plugs to be changed?
Going back to my 1966 VW MicroBus days: (1) hard starts on cold days, and (2) poor mileage. Assuming there are no deposits, it may only require adjusting the gaps. Be sure and use an anti-seize compound when putting them back in. Bob Wilson
