03 6.0l powerstroke high pyro temp?

Put a hypertech max energy tuner on an 03 6.0 powerstroke just got it from a dealer they got on trade in. Was looking for better fuel mileage and am running bigger tires with a four inch turbo back with cat delete. Put the tune on stage 2 and u have to clear all codes first set of codes P0046 P006A P0266 P0460 P0500 P0528 P0562 P1378. Ran fine for a 40 mile trip then the next time It stiil ran fine but the pyro guage is reading higherv used to idle/cool down to 600 and run about 1100 or less when I pulled two bikes. Now its idling at 800 and running without a load at 1200-1300 and jumping to 1400+. Changed tyne to 1 pulled code U0306 still ran the same. Then stock setting pulled P132b and U0306. Then returnd it to the factory setting still running fine but high pyro pulled code U0306 again. Please tell me its a quick easy fix. I do think it has a leak from one of the intake rubber tubes right on top. ???