I have a 2002 accord SE with the 2.3 F23A4 automatic transmission. TodayI was driving, going down a hill not touching the brakes or the accelerator and my engine starts to make this noise that sounded like a kid on a moped was racing down the hill full throttle after me. Had the transmission in 2nd gear and when I shifted to D3the noise stopped. Put the car in D4 the rest of the time I was driving around and a couple of times when decelerating coming up to a stop sign it would make a noise that sounded like a manual transmission being shifted without the clutch all the way in [:'(]. Got back to my house and opend my hood, even with the car in park now, a little throttle causes the car to make the noise as the engine revs back down. Do you think that its possible I have a spun bearing, and if so, when replacing the bearings (if one goes out I'll replace all) shouldI go for new rods with it or shouldI trust the integrity of the rods already in the engine?

 

Just curious how many miles are on your car? I have the same car but its an LX.

 

From the description, it seems like normal downshifting to me ..... maybe a video so I can hear the sound would help.

 

Check your oil level and oil pressure. A video would be better.