My '94 STS has a rattle that has started about a month ago, I thought it might be the front motor mount, I looked at it,(the one at the front center with the brace that goes up to the head), and it is questionable, the brace is about .25" from touching the bottom part of the mount.
But this rattle is not present when parked, and the engine running, I can race the engine, torque it under load, and idling with no rattle.

when going down the road the rattle is there when hitting bumps, or cruising down the highway.
Could it be the catalytic converter? I banged on it with my hand and it seem to have a rattle to it that is similar to the rattle I'm looking for.

thanks for your input.

Stabilizer & link bushings?

I agree with Ranger. It does sound like that's what it could be. I have the same problem right now and need to get it fixed. FYI, my dad has replaced them twice on his 2000 ETC.

thanks, I will take a look at them, and let you know the results

just replaced my Links...did the job....Rock Auto sells after market ones by MOOG...they have grease nipples and should last longer...you can check em by wiggleing them, there should be no play..also check the sway bar bussings.

Torque strut? (the dogbone shaped link connecting the engine to the front of the car.....just guessing (it cured my 'rattle'.....but it sounded more like a 'clunking')

could it be a transaxle?
boots look good, but what would be a easy check for them?
thanks