High milage engine fuel usage?
 

Ok Lucy, 'splain this please. My high milage sbc gets the same mpg it always has and still has good power until a tow load is added. This past weekend we pulled the camper 200 miles and it ate most of 40 gallons in 200 miles. No smoke or over heating and still had good power. What in the world did I experience? Pretty much flat all the way, biggest hill was in the tunnels of the Chesapeake Bay Bridge-Tunnel. Brakes were not dragging on the trailer and the hubs were not even warm. Is it a sign of a badly worn engine when something like this happens? Tune up not too long ago, tranny shifting properly, was not in overdrive while pulling. Any and all ideas or suggestions welcome. Thanks. Craig223, save that Tahoe for me, I may be needing it

What kind of vehicle is it . Also was it windy . MY truck get terrible gas mileage in any conditions . But in to a head wind it suck gas.

1988 suburban, 5.7 700r4 3.73. 287,850 miles. No headwind to speak of. Normally gets 15 mpg, 10 mpg towing.

Re: High milage engine fuel usage?
 

Have I got a deal for you!!!:D :D :D

Do you always tow with the overdrive off?...Higher rpms could contribute to additional fuel usage.

May be a simple reply but is it a 4 wheel drive and possibly forgot to take it out of 4 high? 5 mpg is pretty awful bucky.....not sure if I have any advice other than it sounds like it's time for a new vehicle. ;)

The boat tows ok in OD on flat terrain but the camper is like that dude in the Hemi ads when he pops the chute. One big azz flat front b***h. LOL. 2 wheel drive and yeah I need a new vehicle but 22 years ago we created a little us and the tuition for her and her sister is killing us. The truck still looks great and if we can get another tow season out of it I'll be happy.

5 mpg ouch! I would run a leak down & compression test and go from there. If you have a good vacuum gauge it can also help tell you if you have valve / cam or ignition timing trouble. Would be good to know no load vacuum and load vacuum readings. Just be guessing with out more info. Throttle body EFI?