So you are saying that you changed the table so the high idle runs untill the coolant temp reaches 156 then your idle declines to the factory table settings. http://www.yoursmiles.org/tsmile/no/t2608.gif
So have you tried to shift your truck into gear while your coolant temp is at 150 degrees yet??? http://www.yoursmiles.org/tsmile/fear/t3603.gif