Loud motorcycle noise when accelerating
 

Hello,
I need some help please. I have a 2000 Honda Civic Ex 2 door with 125,000 miles on it. I was driving on some big hills over the weekend and my car was having trouble getting up them/accelerating while going up them. It was not a huge deal, but suddenly, now my car is making a loud motorcycle noise when I accelerate. It makes a softer motorcycle noise when it is not moving, but it is very loud when ever I accelerate. It is a manual, so each time I shift it is loud when accelerating. I just got a new timing belt last year, and an oil change less than a month ago. The noise seems to be coming from the front more than the back. When I put the car into neutral the sound disappears. The car does not appear to be shaking or slipping - it is driving just fine, the issue is the loud noise. It this the muffler or the engine? What could this be? Any advice or experience would be greatly appreciated.

Since you're getting reduced power it sounds like you have a restriction in the exhaust, probably at your catalytic converter. There's a honeycomb looking thing in the cat that can get clogged or damaged. Dont let this go for long.

Ok, I will get it looked at this week. Thank you so much for your assistance! :)

This could be a hole in an exhaust pipe or even a completely broken pipe. Idle the engine then go and block the tailpipe with a rag. Pressure should build up quietly. If there is no flow from the tailpipe at all, or you hear hissing noises under the car, there is a leak in the exhaust system.

Thanks for the advice guys - I really appreciate it. It was looked at today and there is a huge crack in my catalytic converter - so it needs to be replaced. Thanks again for the helpful advice! :)