You've put in all new antenna wiring? That would be the first suspect. Ensure good connections at all of the connectors. Have you got the antenna wiring near any electrical components or their wiring?

It may be a bad ground at the radio or at the antenna. Attach a braided ground strap to the radio and to a good chassis ground under the dashboard. Ensure that there is a good ground at the antenna (at the bezel nut and at the antenna base). Disconnect the radio ground wire when you use the strap.

Does the poor reception happen when the engine switch is at "ACCESORY"? How about when the engine is off but the switch is at "RUN"?

As for the amplifier, measure the voltage b/t terminals 8 (Dark Green) and 4 (Black). Is there battery voltage there? Try also terminal 1 (Orange) and 4 (Black). Battery Voltage?

where on the radio should i attach the ground strap? I know i have a good ground at the antenna because i unbolted the ground and shaved the paint at the bolt location.

I get bad reception pretty much all the time. more often when i am on the move. when i am sitting in my driveway, it seems fine. but when i am on the highway it is terrible, unless i am near boston, it is ok but not good. i notice that when i move the car a couple feet it is good then a couple more and bad and a couple more and good etc. there is no difference whether the engine is running or on accessory when sitting.

Anywhere on the metal chassis of the radio. I have mine on the screw on the back with a nut around it. Don't forget to disconnect the regular radio ground when you do it.

thanks, i will have to try this out. the regular ground is the thin black wire coming from the wire harness?

It should be the only black one attached to the back of the radio.

There is a short cable that runs from your radio to just under your glove box. There is a connector there and the cable runs back to your antenna. Often there is a poor connection here. Also, this short cable is prone to wearing out. If the outer shield breaks, you may have acceptable FM signal, but terrible AM. Play with this cable with the radio on and if this is the problem, the signal will tune in and out. You cannot tell by looking at it if the cable is shot.

been there done that merlin. I already ordered and installed a completely new small antenna cable from gm. No luck. thanks anyway.

Did you try the new ground yet?

i am working on that. i havent exactly had the most time on my hands in the past two weeks. I will try to snag one off an antenna laying around at my dads work

all i listen to at work is FM its cool in the morning because Howard Stern is on but the luch time rewind sucks if i wanted to here songs from back in the day i would listen to an 80's-90's variety station.So when i'm in my bonny it's stricly CD's till the girl get's in the car then it goes to FM. Since I'm gonna shave my fixed antenna. Go to an Audio store or i think Best Buy and ask them for the aux. radio antenna hooks up on your windshield and is powered so u get better reception. and it will run you 30 bucks. my bro didn't want to listen and spent 2 hours hooking up a replacment antenna and still gets the same crappy signal.