2013 Tacoma is bumpy/ driver side feels lower on 2013 Toyota Tacoma

Bought a Brand new 2013 Tacoma double Cad 4x4 TRD and while driving, its bumpy and also the driver side looks sagging.

We took it back to the dealership and they check and say that there is nothing wrong with the car.

I don't know if its a suspension problem or the leave spring is bad. Any one has this kind of problems?

Asked by for the 2013 Toyota Tacoma
Did the dealership offer to test drive a comparable 2013 tacoma for your reference? might be a good idea.
They didn't offer at all. I will call them back to talk directly to the service guy that check the car.
the gas tank, battery, transfer case etc. is on the driver side, weighing it down about 1/2 -1". this is normal, its just bad engineering on Toyota's behalf :( Toytec makes a shim for the front to fix this, don't know about the back though.