Can anyone tell me why is my car system making thump noise and a hissing noise. I installed a different amp and it hisses when vol is at 0

Soounds like it to me.... But to be sure, knowing the make, model & year of the car would be a huge help!

it may be a hose has a hole in it take carb clearer and spray on the hoses if engine speeds up that hose has the leak

There is a distinct sound that has a hissing component when you first turn on the key. It will last a second or two when the key is turned to the run position. When the engine started the sound will return and continue to produce the noise so long as the engine is running.

A relatively low noise is normal. If you are concerned check other like cars for the loudness level.

how to check your fuel pump

The pressure regulator on the fuel rail can also produce a sound when the fuel pump is running. The regulator is under the hood and any reasonable noise would not be a concern, A clicking sound is also normal throughout the fuel system when the engine is running created by the fuel injectors cycling.

Thump + hiss, moving, is a very bad sign.
why not get the car inspected by an ASE tech, mech.
?????
we can not do noise here. only real ears, (in stereo) work.
and lots of other checks.
get is serviced , it might not be safe to drive it.
or is about ready to have a cascade failure.

Hi Shelly, Your explanation is a little short on detail. I suggest that you take a length of plastic tubing and while the engine is running, and the hissing sound is evident, place one side of the tube to your ear move the other end to the different units fitted under the dash until the noise is loudest. Once you've done that you can identify where the defective joint or unit is. Regards John

If it seems to have a loss of power you may have a clogged exhaust, (muffler) system, again if you have a loss of power or it runs ruff check for a vacuum leak.

You need to take your car someplace else. I recommend a ford dealer. good luck.

This is pretty normal, the way the system works is by forcing liquid freeon through a orifice, the liquid turns to gas and gets very cold, the hissing is that process. You might be a tad low on freeon, but you shouldnt be worried.

this noise is caused by a defective power brake vacuum booster, (big round thing behind the master cylinder) the diaphragm is leaking vacuum.

That hissing could be a vaccuum system leak, have youe tried pinpointing the sound from under the hood?