1995 Geo Prizm • 30,000 miles

After the brake and fuel lines were replaced by my mechanic, my car now makes a loud vibrating noise when I am stopped at a traffic light - foot on brake pedal and the car is in the Drive gear. I have taken it back two times for the mechanic to fix the noise but he cannot find anything wrong. I should also mention that after I picked up the car from the first repair session my car leaked gas and the brakes were squeaking intermittently. They fixed the gas leak but again the noise problem from what I was just told is just something I have to accept. Please advise. Thank you.
November 30, 2012.

Check to see if the new exhaust is hitting something under the vehicle and causing the noise and vibration.