I have the exact same truck, the exact same issue when I drive it on long hauls pulling or empty. efi live 24/7 only on level one, RV program designed to not blow smoke at any of the five settings. Injectors are spraying factory fuel amounts on level one.2005, 200,000 miles, no mods
NO. You sound like you've been getting advice from a dealer.pull the plug and purchase a new truck?