Welcome...You may want to look into some maintenance for that Flex as many older 3.5's typically will require some...Plugs, coils, intercooler draining, RDU, PTU, trans fluid, PTU vent cleaning/replacement, valves cleaned.
And your sig really does no good for telling people what car and mods you have..People like to see what you have and what mods you have so they can possibly better help you with issues with your ecoboost car.