low fuel mileage

jmcarter · 08-11-2017, 08:44 AM

Based on my experience with two 5.9 Cummins (both with manuals) 10.5 MPG seems reasonable, particularly towing 70. Have you tried towing at about 1500-1600 RPM? You're likely to get 2-3 MPG improvement and then you can do a cost analysis to see if a gear change is reasonable.

BTW your indicator is probably optimistic by at least a couple of MPG. Also, unless you plan on burning up another stock auto best leave the tuner stuff unhooked.

08-11-2017, 08:44 AM	#10
jmcarter VIP Member Join Date: Dec 2008 Location: Richmond Hill GA (and Port Ludlow WA) Posts: 4,299 Likes: 2,391 Liked 3,194 Times in 975 Posts	Re: low fuel mileage Based on my experience with two 5.9 Cummins (both with manuals) 10.5 MPG seems reasonable, particularly towing 70. Have you tried towing at about 1500-1600 RPM? You're likely to get 2-3 MPG improvement and then you can do a cost analysis to see if a gear change is reasonable. BTW your indicator is probably optimistic by at least a couple of MPG. Also, unless you plan on burning up another stock auto best leave the tuner stuff unhooked. __________________ Jim Carter 2340 Super Stock 2340 SST/2340 Stock Set another place at the table