I have a problem with my car accelerating normally after I drive it for about 15 minutes. It seems as if there's a weird noise coming from the bottom of my car when I try to accelerate, and the more I press the gas, the more I hear it. If I just press down on the gas just half way (which is just enough to get going without much acceleration), I don't hear it. But when I press just a little more, I start hearing it until I let go of the gas a bit which then leaves me with only a minimal acceleration.

It sounds as if there are some beads or something rattling in a tin can when I hear this noise. And the more I press the gas, the louder it gets. And I don't hear it when I first drive it. I only start hearing it after I drive it for about 15 minutes. If I turn off my car to let it rest for about 1 hour, it'll be fine when I drive it for the first 15 minutes and I'm able to accelerate normally. If I'm driving it for about 15 minutes or more and just let it rest after that for just 5 or 10 minutes, then when I turn it on and start driving again, I'll still hear it. It's as if I have to let it cool down in order for me to not hear this irritating noise.

I know my car doesn't overheat since the stick doesn't go passed the middle on the meter. But for some reason when my car cools down after letting it rest, the noise doesn't occur until I drive it for about 15 minutes.

Any help would be very appreciative.

Thanks...

I am not positive on this but a good place to start is go in and get your catilytic converter checked it might be plugged