Pontiac Firebird 1967-2002 - What is that RATTLE?

Hi,
I'm new to this forum. I've had a '98 Firebird convertible (6 cyl) for about 6 years now. I love the car, but I have one complaint. I bought it when it had 17,000 mi. Now it has 75,000. Ever since I have owned it, there has been an annoying metallic rattle in the engine compartment somewhere. I only hear it under light acceleration at slower speeds (0 mph - 20 mph). I have looked many times for it and can't find it. It won't do it sitting still and just revving the engine in PARK. The car has to be in gear, and rolling. Has anybody else in here ever experienced that? And WHAT IS IT? It sounds like it has to be easy to fix. It is obviously just some metal vibrating against metal, but I can't find it. Six years is long enough. HELP!!! :bang:

maybe a heat shield?

I once thought it sounded like a heat shield, so I took a piece of radiator hose and wedged it into the place that I thought might be vibrating, but it didn't help. I guess it could still be a heat shield, but I haven't found it. Thanks.

Check the 02 sensors.

mine just started that crap today.......

Ever since I ran open headers everything in my car started rattling, first the emergency brake, then my console, then this and then that, its making me mad.

You might want to put the car up on jack stands and turn it on and see if you can spot anything from underneath.

my cut out is always open..........

I have that same sound, I assumed it was the exhaust, maybe the low frequency when running at low speed is making it rattle. Haven't had a chance to get it on jack stands to look though.

I have a heat shield loose, but one day the rattle got worse, and really loud. I finally found out it was the passenger cup holder. The metal piece that keeps the cup from falling straight through was loose and rattling. I took it off and I havnt heard any interior rattling since. I still have the heat shield loose... gotta fix that...

Had the same sound here, for me, it turned out to be exhuast leaks around my cats. Once the car was up on a lift, it wasnt too hard to see the black soot marks where the cat met up with the header.

The guy that installed my system didnt do a very good job tightening/sealing those 2 points.

We were able to replace the clamp, and tap the folds out. All is quite now!

oh btw, mine only made that sound when the car was warmed up, never did it cold.

Thanks for the replies, guys. :hail: That will give me some things to check when I get a chance.

Just some more info for ya...
I have a convertable as well & ever since I got my long tube headers installed Ive been hearing that same sounding rattle like your describing.
Turns out the left header was hitting against the something or other.
So you may want to check your headers.