2003 Hyndai Santa Fe - Pushing the Accelerator Makes a Rattling Noise

It sounds like your describing pre-detonation. Try a different octane fuel, or have it retimed.

Are you sure that the check engine light is an evap code? May be a "lean" code? It sounds like it might be "leaning out" and "lean popping". Evap codes are most commonly a bad or loose gas cap, leaking evap canister or hose. Rarely are they because of a fuel pump problem, although I did have a leaking gas tank cause evap codes once. Have the codes checked again and let us know what they are.

I am bringing it in on Thursday again. I will have them recheck the code and get back to you. thanks:)

are they charging you to learn how to fix it?

sounds like they are fixing results, not causes.

One of you exhaust mounting bolts might be loose or missing thus the rattle. The other problem might be the catalytic burner coming apart and partially plugging the exhaust.

Is that something i can see under the car near the exhaust pipe? I am not sure where the mounting bolts are. Is the catalytic burner something I can see? You're right, they are definitely just fixing the results of the main problem. But no one else has the right scanning tools to fix the dang thing.

Any vehicle sold in the USA from 1996 on must be OBD II compliant. Autozone will scan OBD II vehicles for free. Find out exactly what codes are present and let us know. Then we may be able to help you find the "root cause". Catalytic converters can cause a loss of power and a rattling noise. The easy way to check this is to drive the vehicle until you have the problem. Then pull over in a safe spot and look under the vehicle toward the center and see if you see "something" glowing "cherry red". If you do, you have a catalytic converter problem. But, it sounds to me more like a lean condition, which could be a fuel flow problem, but more likely an air leak in the induction system.

No!!! The catalytic burner broken pieces are plugging itself; eventually the motor will have no power; it will only be able to idle, simply because the exhaust gases can not escape. Too much back pressure. You will have to be towed in.

Something loose between the exhaust manifold and the burner.

The noise --if fuel knock-- can be caused by ignition timing incorrectly set; coolant temperature to high; EGR valve plugged (will usually set a check engine code). Too little ERG will often cause engine detonation knocking as you describe.

If the noise is not from inside the engine, but external, it can be a loose heat shield, a failing catalytic convertor--loose baffel inside- a failing exhaust pipe (some are double walled to keep exhaust hotter going to catalytic muffler.)

'Knocking is a description that applies to many causes. Any further description helps

I took it to the dealer who said that the check engine light and diagnostic revealed a tiny leak just above the gas tank. He said it was harmless. the rattling that sounded like tin cans when I push on the accelerator was aparently not anything to worry about as he dubbed this noise,"normal for Hyundai Santa Fe's". I have been driving this car for three years and it is NOT normal. he says that nothing else is coming up on the diagnostic and said to bring it back whenever I have more problems. So much for trying to catch the problem before it got too bad. Guess I have to wait for it to break down first.

A guy at work had the same rattle and power loss at 50,000 miles and it was a clogged cat.