Snake oil? I LOVE snake oil!
I checked my odometer today against a GPS and it's off by less than a tenth of a mile every 25 miles. Is that within parameters? I've blown most of the carbon out of it the past 2 wks since I saw Terry and am ready to re-fill but since I've been a little lead-footed these past 2 wks I don't think my MPG's will be up by much
Next is a trip to a very highly-rated diesel truck mechanic....