Ever since I bought this car in March 05, I noticed a slight engine noise. Appearently NOBODY (including two GM Dealerships) could find it or tell me what it is. I had the car sitting for a couple months during winter and now when I start it up from a cold start(been sitting for more than 3 hrs), Starting from 1500rpms you can hear a knock when you press the accelerator. The sound will only last for about 500 rpms then quit and sound perfectly normal. I have captured this phenomena on video to see if anyone can finally put to rest what the hell this is--but unfortunately the file size is 8.36megs so I have to use alternative means to host, The video is on YouTube.com - web address: http://www.youtube.com/watch?v=AJguCAd5vk0 . BTW, After the car warms up a bit, this problem disappears. Ive been told several possible things but nothing for certain. Its most unlikely to be a rod since its sounding like its coming from the rear of the drivers side engine under the valve cover and it doesnt do it at idle, but who knows.

 

Well I guess nobody knows.. But thats ok, Ive decided to trade the car in on a 2001 Z28 with 55,000 miles, T-Tops, and a Monsoon System. So, I have some things for sale that I will post in another post.

 

it could have been piston slap, lifter not pumped up , or an exhaust leak. im thinking piston slap