Pilot reported engine failure on approach to landing. After a safe landing was accomplished; the aircraft was determined to have a problem with the fuel lines by a local mechanic.

Narrative

An engine failure during an approach. I was the Pilot Monitoring for this flight. We made it to the field and landed safely. We depart ZZZ at XA:47 PM; perform an approach at ZZZ1 and ZZZ2; and when preparing for another approach at ZZZ2; we notice a drop in our RPM; then the engine stops; we perform the procedure for a landing without the engine at ZZZ3 and make it to the field safely. After landing; we notice an imbalance in our fuel tanks. The left tank was lower than the right tank. The fuel selector was positioned on 'both' during the flight as we performed the before-take-off checklist and before landing. The fuel gauges showed the perfect amount of fuel before the engine started; but the plane vibration made the needle swing once it started. We also estimate the fuel based on our calculations. Our Mechanic told us we had an issue if our fuel lines which caused us to lose the engine power. As a Pilot Monitoring; I help my Pilot Flying directing him to the Runway; and also performing the ABCDE checklist after an engine failure. He lands the plane safely.