I was getting the P0128 thermostat code quite frequently once it became cold out and it seemed that my car took forever to warm up. I installed the Motorad 180tstat back in Aug. of this year. Last week I had a bad leak from the tstat housing - found that when I installed the Motorad tstat using my original rubber gasket that I it rolled over inside of the housing and was damaged. The Motorad was a very tight fit. I installed a new Jet 180tstat and now my car warms up alot quicker than the other thermostat and I haven't gotten the P0128 code since. You might want to get another thermostat. The other code I'm not familiar with - might want to talk to the dealer about that one.
The 505 used to be iac valves back in the day, nowadays your car has an electronic throttle that it controls. Even when you foot is not on the throttle the throttle is open a little so air can flow and the engine can run. Something is wrong with this system, which is your etc (electronic throttle control)