Starting to get a lil iffy now fellas I only had my tls for about a month so far and olready had alternator fail now today just got the check engine light & code p0171 p0174 car running lean could that be triggered by taking my mid muffler out! Car only has 36k!!!! Even though i'm still under 100k wRranty I would like to hear from ya what it is before dealer tries to screw me like usual... Should I run fuel injector cleaner if so which one redline or seafoam or should I keep drivibg like that till my apointment???

 

MM delete shouldn't cause a problem as the code is a lean condition bank 1.
Here's some reading:
http://repairpal.com/OBD-II-Code-P0171-and-P0174