A perfect rating (158.3) requires at least a 77.5% completion rate, at least 12.5 yards per attempt, a touchdown on at least 11.875% of attempts, and no interceptions.
Easiest way to do this (imo) is to throw one pass over 13 yards and score. Very simple if you're playing on rookie, with all of your stats up and theirs down. A good idea for this is to run a fake field goal from about the 20. Make sure your backup isn't terrible, and throw it to the "X" receiver when he is in the end zone.
Then you can still use your regular QB without worrying about this.
Btw, I was actually able to get this in Superstar mode as a RB, so if you're lucky, your QB will do this for you. (If Gerrard can do it for me, anyone can for you.) (I also got the 2 pick 6 achievement this way. I'm not sure how many this will work for if you get really lucky, but I assume any are possible...)