knocking noise

[Cheng]

I was driving it the other day and after i stop i started to hear this knocking noise coming from my engine.  The noise only happens when its at about 2000 rpm when in neutral and when i'm driving it happens when i hit the gas and letting go of the gas

[Broadwayblues]

make sure that it is not the a/c compressor. I thought that I had the same problem but whenever the a.c was off, there was no sound.

[Cheng]

well i don't have ac

[camppain]

if its more like a popcorn popping noise could be a spun rocker arm stopper

or the inevitable spun rod bearing. to see if its a rod bearing pull one plug at a time if the noise decreases then you have picked the right cylinder. for a spun rocker arm just pull your valve cover and see if you see one out of place.

[DuffMan]

Maybe its a JDM mouse trapped in your engine. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>

[ridebmx]

id say that its a spun bearing...which kinda sucks because you will either have to get your crank machined(never did this, heard they arent as strong anymore)or buy a new crank, bearing set, and one new rod...that is if you dont want to build the whole inside once you have it all apart...better hope its just your rocker arm like others said it could also be...