My car developed this knocking noise after about 2.5 months of almost no use. I would use the car sparingly. Here's a clip of the sound, you can start to really hear it at about 10 seconds.

http://www.youtube.com/watch?v=C2ilKNxCXMw

 

Perhaps the gas has gone stale. Try adding octane booster and run down that tank and then refill it with fresh gas.

 

Does the sound change with engine temperature? Which part of the engine is knocking? (top/bottom) Did you check compression? When did you last change oil/check oil level?
There are quite a few moving metal parts in the engine, and almost any of them can be the cause.

 

wow..hopefully aint a rod..like the above statement where's it coming from top or bottom ?

 

It sounds like it's coming from the top. The sound doesn't change with temperature but it does sound faster when the rpm's go up.

 

a hole in the exhaust manifold or gasket?

 

Sounds like a noisy valvetrain to me. When was the last time you changed the oil?

 

I think it was back in August but that's because I used that Mobil 1 Extended Performance oil that you change once a year. I might go ahead and do an oil change to see if it helps.

 

hey man thats a bs stuff the synthetics oils or the one u used, its not worth of ruining ur engine just use toyota oil, or castrol and change every 3,000 and you'll have no problems with any noises


OIL IS OIL!!!!!!! lol

 

Almost 3 years later that knocking noise finally came to a head. Turned out to be something simpler than I thought, a spark plug . Car is like new .

 

would be nice to see the condition of the spark plug