i have a 90 ef si.
when i am driving it it starts to rattle alot from the passenger side. and once i hit about 40 mph it stops and runs way smoother.
is this an axle problem or wat could it be?

 

tire?

 

I doubt it's a tire. Check your axle and alignment (though alignment would make ride rougher at high speed). It kind of sounds like torn boot and grease has come out. Possibility is that axle could seperate from cup. Does it make any noises when you turn either left or right? This happened in my Eclipse and I hear a clanking sound when I turn too hard.

 

A tire will make the car shake if its separated or has a bubble on it. Alignment will not cure any thing but tire wear or a pull. Also it could be a wheel bearing. try rotating the tire to the back see if the noise moves. if it does then its the tire.

 

Jack up the car and check to see that everything is on tight, nothing in particular looks torn to **** and then move on the what was suggested

 

If it was the wheel bearing, it'd rattle above 40mph as well. I had this issue with my EF hatch. Jack car up and try to move tire around. If it wiggles, then it's probably your wheel bearing. Replace this AS SOON AS POSSIBLE!!!! I cannot stress that enough. The bearing could cease at anytime causing a major headache. If it's coming from the front, dont be burning out or driving like crazy because it will put more stress on it.

 

tie rod ends? unbalanced tire