rattle noise under car

[ahardb0dy]

94 Q45 t , 159,000 miles. I'm hearing a rattle noise it sounds like it's under the car (like behind the transmission) sounds like a heat shield to me but have no way to get under the car. Noise is only present when A/C is on and transmission is in either reverse or drive. If I switch A/C to economy noise stops, if I put the transmission in park noise stops. Can't really tell if it's on one side or the other sounds the same from either side. Any ideas? Thanks

[elwesso]

Pretty common on most nissans.... I had this probelm with my old Q... Loose heat shield on the catlyitic converter. I put something into it to hold it tight... I eventually went over something that ripped the heat shield off anyway!

Does it do it *everytime* the AC is on and your in drive or reverse? And can you feel it, or jsut hear it?

[Q451990]

Sounds like it happens at a lower RPM than your base idle. You might be able to set it down with the IAC, put it on jack stands, and then check it out then. I have also had some success crawling under there and just banging around until I find something loose.

Heath

[elwesso]

I have also had some success crawling under there and just banging around until I find something loose.

Heath

Thats also more fun!!

[ahardb0dy]

no, I can just hear it can't feel it, it doesn't make the noise all the time when it's in gear, this afternoon I had the A/C on and the car in gear and it didn't make any noise.

[elwesso]

I bet its the heat shield....