YJGTO

Hello everyone, Went to work this morning, Came back, started my car and now i have this going on. Its an 04 LS1 GTO, it sounds like a lifter or an exhaust manifold leak. The car still runs top notch, but it sounds like dogshit.
I just want to narrow down the possible causes, as this is where my tax return check will most likely be going.

I pulled the valve covers. All the rockers are tight. Here is what I dont understand, the car only makes this noise once in a while. If you get the car up past 2500, it becomes really loud. If you keep it below 2k, the tapping slowly goes away and stops. The car is stock. It's just hit 93000 miles. Had its routine Mobil1 oil changes as well. I just want to get the collective knowledge of the forum before I start digging in.

Thank you in advance for any help you can provide.

http://www.youtube.com/watch?v=8Zr4q...mhyz5zct7PBSHL

2000PewterT/A

I had the same noise from my car a while back, after I tore down my engine I found out that there was a very worn wrist pin on #7. Not 100% sure if you have that problem but I would definitely check the pushrods and investigate until you find the noise. My car had 74k miles on it when the noise started.

prokilllsx

It sounds a little different from most lifters I've heard after their needle bearings started running away. A little closer to what my 98 Formula sounded like after the ball broke off the top of a lifter and grenaded the lifter bore. Are exhaust manifold leaks common on LS1's?