loud noise and shimmy - dealer says everything OK
 

i am a newby here. have a 2003 touring. when i hit 50 mph, i get a loud noise from below the car - sounds like muffler problem -and a shimmy that feels like flat tire. seems to correct itself at 60+ mph. very annoying. also, loud noise when braking. dealer ckd it out and said no problems - just as i expected them to say. i don't believe them. any ideas what may be wrong? thanks.

Did they test drive it or just give it a visual instection?

The loud noise under braking suggests you are experiencing the tire cupping issue. I have experienced loud resonances and what not from the tires due to this. Have the dealership inspect the tires and do a test drive. Also, call 1-800-NISSAN1 and tell them about your experience.

Derek