91 civic - rattle in front end

i have been hearing a rattle in the front end of my 91 civic dx. it only appears when i'm moving more than about 20 km/h whether i'm in gear or in nuetral. it rattles more as i go go faster. i thought a rock might be stuck in my wheel-well but its been almost a week and i can still hear it. as well, the car drives exactly the same as it did before i started hearing the noise. any opinions wuold be appreciated.

Does it only happen at certain rpm? Try putting the car in neutral and slowly increasing rpm, it could be your cat. Something broke loose in side it, OR it could also be the heat shield on your exhaust, both things to check.

Either your wheel needs balancing or your axles and ball joint's are shot. The axle boot can be intact but the inside could be broken...does it click when you turn? YOu may have to jack up the car and fully inspect your supension to be perfectly sure...at this point we're all guessing..

When you say it rattles worse as you go faster, does it increase along with the speed of the wheels..or does it just generally get worse.

Would your rattle sound more like a roaring sound? It sounds to me like you may have a bad wheel bearing. Take the car on a test drive and see if the noise increases when hanging a left or right hand turn while the vehicle is traveling at 30mph or faster. If the frequency or pitch of the noise doesn't change on turns then you can rule out the wheel bearings.
Other possible sources of front end noise:
Bad tire surface (visual inspection should rule this out)
Bent or damaged backing plate riding against the rotor.(Visual inspection...)
Bad main bearings within the transmission. (Does the noise change when the clutch is depressed while the car is moving?)
Bad pressure plate spring. (Does the noise change when the clutch is depressed while the car is moving?)
GOOD LUCK