maybe you have a muffler problem
Nothing is wrong. Your stomache is digesting food, but making noise while it does so. Your stomache is constantly making noise, though it is only rarely audible.
Depends on where the noise is whats making the noise. Can you be more descriptive of where and what?
If your 88 CRX SI alternator belt is making a strange intermittent noise shortly after changing the alternator what's wrong, the belt tension could be off. Adjust the belt slightly.
There could be a number of causes. If the car is making the sound whilst stationary it could be a slipping fanbelt, or could be a problem with bearings. Water pump bearings are a common cause of such noise. If the noise is occurring only whilst travelling. It could be wheel bearings or rubbing brakes.
Could be the wear indicators on the brake pads Last time pads were replaced?
Anti-rattle clips not installed properly
It could be called distrortion, or noise.
With out hearing it, It is hard to say whats wrong. But the most common noise like that would probley be a ROD knocking. Time for engine overhaul.
It may be the Idler pulley. I used to have a 96 Breeze with a 2.0L 4cyl that made a whining noise. I thought something might be seriously wrong, but then i discovered it was just the Idler pulley making noise. I changed it-- no more noise.
The two main reasons could be either a leak or a hole. I'm not very knowledgeable when it comes to cars, so I'm probably wrong.
propshaft coupling is damaged
look for a disconnected or broken vacuum line. Clogged Catalytic Converter making a hissing noise! Does it lose power pulling hills? bad gas mileage etc?