Stick with the two-nut method, and use a proper-sized wrench (not a Crescent) or, if nothing else, a sturdy Vise Grip on the nut (not the stud, itself). Add a few squirts of PB Blaster. If it still won't budge, add heat, then spray with PB Blaster so it sucks it into the threads. If it STILL doesn't come out ... resort to using plastic explosives.
everybody else pretty much covered it but I take off the tb and egr spacer, if it's not rusted in place....spray in some PB, get a good bite on the stud itself with vice grips and add heat if it still doesn't come off.....ive had to use a mixture of pb, heat, flathead and a big hammer to wedge the tb and egr plate off before from the coolant seizing everything together.