Had a 1999 Tacoma, leveled, etc. It got like 17 mpg. I can't remember the payload, but once loaded MPG dropped to about 15. Good truck. Never an issue.
Then got a 2013 F150, 5.0 V8, with a 1649 lb. payload, I had some tires on it and a level kit. Nothing over the top. Never got better than...