My car has been parked for over a year when i cranked the motor i can hear a knocking noise but only when i press on the gas. there is no noise when the car is running only when i press on the gas.

could be oil pump its self,dode oil pressure go up when throttle is applied,or dose it have a seperate oil chain thats worn,all the best.

big ends camshaft water pump

There are many possibilities that can cause car to make noise.

It's actually from where the noise is coming from. Front end or rear end. From engine area or from inside the steering or from brakes.

There is N-number of possibilities for the car to make knocking noise or any other kind of noise.

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For step by step troubleshooting this problem, I suggest you to refer the help links mentioned below. Its a complete solution with proper explanation to identify the cause of problem: ------

Click the link below: -----

CAR NOISE ISSUES
http://alltypesofpartsreplacing.blogspot.com/2012/11/car-noisesnoisy-cargrinding.html


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These will help.

Thanks.

if the noise is coming from the bottom end of the motor then you have either bad connecting rod bearings or bad crank bearings.if when you snap the throttle you hear a double knock then its connecting rod bearing if not then its crank bearing.a collapsed piston can sound low in the engine and its usually a dull knock noise.if you have the engine running and the noise is there and you pull off one plug wire at a time(and reconnect it after checking) and the noise goes away or mostly goes away with the wire unhooked then the cylinder that the noise changed is the cylinder that has a bad piston.

Well the reason with out hearing or seeing it sounds like you have either droped a valve or done a big end ,which is the white metal bearing slippers on the bottom of the con rod which is connected to the piston in 1 of the cylinders and in turn makes a bad knocking noise before doing damage to the rest of the motor BUT you dont have to buy a new motor as get a few quotes on engine rebuilds as done by a good reco shop it will last for years ..
IF you get a s/hand one then make sure you hear it running for at least 1/2 hour and make sure its good oil pressure and dosent overheat and no noises from engine at all,also check the engine number with the Police Just in case???? engine can be hot in more ways than 1..
Let me know how you get on and if i can help anymore Ron

if it only knocks or clunks puting in gear or gettingonit I would check motor & trans mount both upper dog bone & cross bars to core support

check the vehicle knock sendor, are u using the right grade of gas, and oil for u temp zone

Engine knock Huh? In order to qualify the term "Knock", Let me get you to perform some simple task/observation. Typically, if you hear a noise on top of your motor that can be described as a light knock, usually going tap, tap, tap, tapping along at double the tempo, of your motor spinning, Your oil pump may be having trouble getting oil to the top where the valve's and rocker arms are. If you hear a "Knock" by bending over or kneeling beside one of your "front wheel well's"and stick your head up to the well, providing a vantage point to "hear" whats going on at the lower part of the engine. A knock from here will/can indicate a potentially overheated, under lubricated, rod or crank bearing that could seize the motor. This (theretical) crank bearing would be sounding off at half the tempo of the rocker arms above., with a deep, dark klunk that would defintly present itself as the sort of noise that damages metal parts. Now, that being said.....common sense goes a long way, people....1.) Most people are aware of the maintenance that has been performed on a particular engine, the quality and quantity of that maint. and when the last time it was ran out of oil or water. For those who fall into the " lack of maintenence" catagory, you probably already know why your engine or driveline sound as it does. If you happen to take particulary good care of your car, there is a good chance that whatever noise or "happening" might be going on, it'll be much easier to remedy. There are always exceptions to every rule. Remember, its not what will happen, it's what can happen. Take care of your car, and it will take care of you. Theroad

IT MAY BE A CV JOINT DOES IT MAKE MORE NOISE IF YOU TURN LEFT OR RIGHT

This is most likely either a piston noise or a connecting rod bearing knock