Every time I turn on my engine I get this rattling sound from under the hood. It goes on for about 15-20 seconds and than its stops. I tried to see where its coming from and it looks like its coming from ABS. Does anyone have that problem and how can I fix it?

 

If it's the ABS start-up sequence... you should feel it very slightly in the pedal. It's more of a hum than a rattle and only lasts for less than 2 seconds.

 

Its a rattling humming sound that last for about 10 if not 15 seconds.

 

Could it be comming from the exhaust under the car. Heat sheild on the catalytic converter will often resonate at 900-1100 RPM... which is a typical engine speed for idle when the engine is still warming up.

Does it go away if you rev the engine or if the RPM changes. 90% of rattles and humming nosies are usually tied to a specific RPM or the pitch will vary as the RPM changes.

 

Actually I dont really rev the engine when the car is cold and especially now that its very cold in NY. I start my car and sometimes when its cold my engine starts close to 2000 rpm.

 

sounds like nothing serious.

 

If the cat is bad, is might break apart and rattle. You can hit the cat with something to see if there is rattling in it. I had a problem like that with the cat in my old corolla, it would rattle sometimes. When I fould out it was the cat I just got rid of it.