Help Diagnosing Noise

[joe29]

I'm currently experiencing a loud rattle/knocking noise coming from my front passengers side wheel area.  I have a 2005 RX330 with 186k miles.  The noise sounds like it's metal to metal contact.  It occurs when driving over the slightest of bumps or uneven pavement.  It's a constant noise when driving under 30 mph but seems to disappear when traveling at freeway speeds.  Additionally, my TPMS light comes on after about 20 mins of driving although the psi in all 4 tires are fine.  

Any ideas of how I can diagnose the problem?

Thanks!

[exmeaguy]

Maybe a loose heat shield.

[TrevC]

I don't think the two problems are related but the knocking could be a worn anti-roll bar link.

The TPMS may just need resetting with some diagnostic equipment.

Let us know how you get on

[jetfixer01]

Do you have a full size spare tire? If so, you have another tpms sensor in it.