HELP PLEASE: Engine makes "Rattling" noise at lower RPMs...

I have a 2003 I4.

I'm not sure if this is a common problem or not, but when I am accelerating at lower speeds, usually around 1200-1800 RPMs the engine makes a loud vibrating/rattling noise, and I am unable to pinpoint where it is coming from. It sounds like it is inside the engine, or behind the engine, or even under the engine. But it does get pretty loud at times and only happens when I am maintaing a speed within those RPMs or accelerating within those RPMs. It is not heard above 2,000 RPMs or at higher cruising speeds.

Does anyone know what it could be? Perhaps a lose bolt? heat shield? or catalytic convertor? If so, can you guys tell me how to check these items?

I really appreciate any help.

Thanks!

Are you sure it's not the valves "pinging" under load instead of a "rattle"?

i am thinking it is the heat shield. Check that. and depending on the mileage, chcek ur CAT

i am thinking it is the heat shield. Check that. and depending on the mileage, chcek ur CAT

Where is the heat shield located and how do I check it?

Also, what about the CAT and what parts/how do I check it?

Do I have to drive it up on ramps and let the car run while I listen/feel around (with oven mitts?) to try and stop the rattling?

Thank you so much for the suggestion!

its your intake manifold. Theres TSB for it http://toyota.justanswer.com/uploads/skyvisions/2008-10-03_123233_02_camry3.pdf

agreed with above...its the intake manifold TSB....ive replaced quite a few of those...i lucked out on my 03 and the issue doesnt apply

The PDF link did not work but I was able to go to Google Cache and get a TEXT version of the PDF file and copy/paste it into WORD.

Will an extended warranty cover this TSB/issue? If not, is it a part that I can easily replace myself?

Thanks!

It should be.

I have the 6 year, 100k extended warranty. I just got off the phone with the warranty company and they said that the Intake Manifold is covered.

Now my question is this, is there any way that they can deny coverage? Saying that regardless of the extremely loud sound that it is not completely 'failed' ? I mean I wonder if since it still "lets the car run" if they will try to deny it?

I have noticed reduced performance since it has gotten significantly louder as well.

I just want to know how to "Fight" this and to ensure that it is covered.

Thanks!

I had the manifold replaced and it fixed the problem!!! Thanks guys!