Squealing noise/vibration, please help

[blitzkrieg59]

Hey guys and gals, I'm new to 240's so bear with me. My girlfriend owns a 94 240sx Convertable auto and she has been having some problems with it. It was wrecked a while back but rebuilt by the body shop. Since then however, the car vibrates quite a bit at idle. My first thought was maybe the vibration dampner was off balance. The car does, however, idle too low at about 6-700 rpm. What should I try?
Also, recently the car has developed a rather strange noise. It's a very faint, high-pitched sound that could almost be described as metal to metal. I thought at first it was the brakes but the strange thing is that the sound dosn't seem to correspond with anything, it just goes on and off seemingly with no reason. It's comming from the rear of the car. Is there a fuel pre-pump in the tank that could be making this noise? Any suggestions?

[aznpoopy]

does the idle fluctuate or lights dim when u turn on accessories? clean your engine grounds and/or buff up your existing grounds with more. check alternator output, etc. standard fare for old cars.

if the motor shakes around alot all the time (esp startup and shutdown), and throttle lags; consider fixing motor mounts.

idleing too low... lots of stuff to check. i would start with timing. does it fluctuate? set idle speed, etc.

metal on metal noise... i would guess brakes. the pad is just starting to get low and that wear indicator is just starting to tap intermittently against the rotor.

good luck; as with any old car you are just going to have more and more problems until u get around to putting some time restoring it.

[blitzkrieg59]

The idle dosn't fluctuate. The brake pads were just done a little more than a year ago. When I get time I am going to have to give it a really good once over. Thanks for the help!