I may not be the one to suggest this with the issues I have had with mpg but I added E3 spark plugs and increased my mpg by about 15% for 10 years. Then other issues decreased it.
Ron, The Computer Greek I love therefore I am. 1954 3100 Chevy truck In the Gallery 2017 Buick Encore See more pix 1960 MGA Roadster Sold 7/18/2017