RepairPal Certified shops can diagnose and repair your 2003 Mitsubishi Lancer. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
When my flex pipe had a hole in it I lost a lot of power and it started to make a loud noise. It could also be the EGR, cat, oxygen sensor, etc, need more information, and a diagnostic code if you can check the check engine light data (if its showing up).