LDS777
Member
I have the HD tow package and just had a tune up, replaced 2 coil packs and fuel injector service. The first time I towed a 3,000 trailer I noticed black soot all over the tailpipe, and only got 10 mpg ; there was no check engine light. SUV runs good but runs rich in tow haul. What fuel mileage is expected in tow haul and why does it run rich? Everyday fuel mileage is approximately 18 mpg.