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#21
Had 2 4x4 Blazers with V6s, and both of them .. 17-19MPG was about average.
If in that range, I think its normal and about the best its going to be sadly.
I remember a while back there used to Split-Fire Spark plugs that claimed to give better gas mileage. Not even sure if they still make them though.
But if I recall correctly, they did help, but very little.
It was less than 1mpg, more like .5