My engine light came on and I took my 2006 Silverado in to get checked out. The guys checked it out and it was my O2 sensors and Catalytic converter. I figured that's what it was as I plugged up my code reader and saw the codes. They worked with me (because this is a HUGELY expensive repair) and they fixed it very well. The truck drives 100% better and no rattling noise, etc. I really appreciate Guillermo, Kevin, & Modi. Great team!