Here's the issue....I repalaced the radio, front and rear speakers, antenna and antenna wire and it sounds great with the CD and IPOD aux, but when I put it on radio receiver sound is poor can barely understand the vocals. Could the 6 X 9 rear speakers be too big and not enough power to push them and suggestions would be appreciated.

The speaker size is the same whether you're using the CD or ipod input, so that's prolly not the problem. I'd suggest there is an issue with the antenna, or the tuner itself. Does it not sound right AM and FM, or just FM, or AM?
When you replaced the ant., did you also install/re-install the ground plane that fits under the bodywork.
The ground plane is an aluminuminum sheet with a strap that connects to the chassis. The ant. goes thru this from underneath. A fiberglass body doesn't provide enough of a ground plane for decent radio reception by itself, so they put the ground plane on Corvettes. On a metal bodied car, the whole thing is a ground plane, so you can get away with using an embedded ant. in the windshield...which GM did for years.
Make sure you have a plane on there first...

Now I'm not sure the later cars had the ground plane....but they have to have something to act as the same. Anyway, here's whut I'm talking aboot....


                                                     cleekAdams' Apple2009-01-23 11:08:16

I think Joel is right, antenna problem, and maybe the ground plane.

I am going to work on car in AM will redo ground and let yall know