I had similar issues back some time ago....But I was going into limp mode from time to time, but no codes...After 3 trips to the dealer and nothing...it finally started to do it really really bad one day...had to limp mode all the way to work...stopped by the dealer and all of a sudden NO throttle response...just idled....turns out it was the TPS and TB both shot...new TPS and TB and no problems since....

 

ha..i posted too soon bc my car went to failsafe AGAIN..i thought by cleaning the tb i fixed it but NOPE....so im hoping its the tps.....and the quest continunes