I was doing some standard maintenance the other day on my Lexus and I noticed that I had a crack in the tube going up my throttle body so I took care of it by sealing it off an assuring there were no other cracks anywhere. I saw a few and tended to them. I also patched up a few small leaks around the beginning of the air intake. I started it up immediately after and it ran absolutely beautifully, I've never seen this car like that before. It did so for the rest of the night when I was driving it as well. It's throttle lag was gone as well as it's general sluggishness that I thought was just part of the car's personality. After about two days though it returned to it's normal sluggishness and I have no clue what could have caused it to run how I assume it's supposed to. I've been going through everything and I can't replicate my success. It also has stored codes for p0171 and p0174. Any thoughts? Thank you in advance...