sounds like you have a broken or worn out shock absorber Another possible answer: The Struts can be worn out. Easy way to test struts is to back off the center nut on top of strut. DO NOT TAKE NUT OFF!!!! Push down on strut shaft until it bumps the nut that you did not take off. If the shaft does not come back up, the strut is worn out. If you have difficulty pushing it down, It is ok. note: the reason you do not take the nut off is that if the strut IS bad, you wont be able to get the nut back on the shaft after you push it down. If the nut IS NOT secure on the shaft.. DO NOT DRIVE THE CAR! and another possible answer. Check the right side motor mount. I found mine to be torn and bottoming out on the bolt that goes through the center of the rubber. To check this, get a small pry bar and find a place you can pry up the motor near the mount. All you have to do is lift it 1/4 to 1/2 inch up then let it go fast. If you can duplicate the knocking sound. You found your problem. I found this out after replacing two struts (they were bad anyway) and two strut mount kits.
I found my noise wasn't something loose. It was the rear strut was bad. Was more of a load squeak that sounded like something knocking.
If the noise is coming from the rear then the bushing is broken.
check heater blower motor blower wheel could be broken off The knocking comes from an Acctuator that has stripped out in the Hvac case. You Have to replace the acctuator to solve the problem.
I get knocking & ping noise coming from the fuel injectors
if it sounds like the knocking is coming from the bottom of the engine i would bet it was the rods or rod bearings may be worn. if the knocking is on the top ,then i would have the lifters and or the rocker arms checked.
A other small child
My 2000 Grand Prix would have a low-speed knocking noise coming from the drivers side as the CV axle was failing. The loss of lubrication in the CV Boots allows the joint to make a knocking/tapping sound at a low speed. If the knocking is coming from the engine compartment, then it could be an entirely different problem.
have you tried higher octane fuel?
Cant you just ask the people at the car place?
If its a legitimate knocking then you would want to go with head gasket if its a tapping you would be looking at a valve
Where is the noise coming from? If its from the fenders or wheels is a much different problem than if its coming from the transaxle.
Its hard to say... do u know where the noise is coming from?