I have a 2003 ford focus. For probably 8 months now, my car has been making this loud rattling noise which seems to come from the right side of my car. I had it checked out by a mechanic when I first heard it and he said it wasn't anything to worry about, something had gotten loose, and he tightened it for no charge due to the simple fix. The noise returned probably a week after that and I've been driving with the noise ever since. It always happens when I accelerate and turn right. It's not noticeable when I turn my car on, turn left, or hit the brakes. The noise seems to be less noticeable when the car has been running for at least 15 minutes. It seems to get worse when my gas is lower. Along with the rattle, my car tends to vibrate from it. So much so that I barely use my rear-view mirror because everything is a blur.

If you know what is wrong or have had this problem before, please let me know what you did to fix it. I'd really appreciate it.

 

I would say first if you have vibration that bad, your motor mount over on passenger side is bad. They may look just fine, but measured against a new one tells a different story. We have a 01. Motor mount looked clean, sound shape, but caused a terrible vibration to where looking in the mirror was useless. Put a new Ford mount on, and it was like a brand new car! Do not get a aftermarket mount for that one either. You will probably have the same problem. If I remember right they have oil in them, for a aftermarket will not.