Let me first start by saying the car drives fine at all speeds and idles normally...but if I put the car in Park or Nuetral (atx) and quickly rev it up to 3k rpms or more & release , there's alot of engine rattling noise as the as it revs down intil it get back down to about 2000 rpms. But if I rev it up and slowly bring the rpms back down then it sounds normal. I noticed it about a month ago but I just though it was the headers or some exaust pipes rattling but i checked it out yesterday and it's definitely in the engine. I'm thinking it's coming from the head but i'm not certain. It doesn't happen while driving because it's an atx so the rpms never drop fast.

Could it be insufficient oil supply, worns valves, or what?

I'd appreciate any opinions.

How many miles are on the beast? Could it be lifters? I know they can start to get noisy when they go bad.

there's about 137k on the motor...it's sounds pretty loud to be the lifters, but then again, it's not like i know what really bad lifters sound like. whatever it is, it doesn't like when I rev the engine quickly. it sounds sound kind chaotic until it idles down

If was the lifters, it would be like a clicking noise and the higher you brought your rpm,s the faster that clicking would get.

I hope its not a valve tapping

it definitely isn't a ticking sound. it's more of a fast rattle. If the timing wss off, would that cause the valves to tap? Although I had the timing belt replaced last year. i guess it could skip a tooth or 2

Is it running bad? If it even skipped a tooth, you would notice a change in the motor.

No, it runs fine...so I guess I can rule out the timing belt. What does a spun bearing sound like? I did a search but didn't find what I was looking for. Oh, and thanks for your help with this :thumbsup

Spun bearing would be noticible under other circumstances. Look at flexplate that Torque Converter bolted to and make sure that it isn't cracked. Had that happen and sound the same under similar condidtions. Could also be several other things. Start easy first. LOOK for loose shit.

sounds like an intake backfire to me. is it a sequential popping sound?

are you using the stock exhaust mani?

theres that little jib to sticks out the side (right) and a weld brke and it caused this annoying ass rattle above 2500prms.

ok, i checked it out today and it's not the exhaust/flex pipe section...i have obx headers, so there is no manifold bracket to rattle. and it's not intake back fire... but it's definitely in the engine. i guess the best way to descride it is it sounds like a bunch of bolts in a metal container being shakin VERY fast.

i think the best symtom is that it only makes the noise during quick revs.

Hmm could be a piston pin problem maybe too much clearance in it .. ive seen that before kinda sounds like an m16 goin off and usually only does it when lettin off the gas at a higher rpm..

now that sounds interesting...do u have anymore info on this?

My money would be on a spun bearing. Sorry, dude.

Originally posted by Ducking_Fumbass
My money would be on a spun bearing. Sorry, dude.

either way its bad .. id rip into it now before something goes shootin through the hood.. we can get you stock engine rebuilt kits for like under 200 bucks if you dont have the money to doa full race rebuild