I have a '01 Z28 with 5.7L Ls1 132,000 miles. I've only had this car about 3 weeks but only mods that im aware of are headers, slp ram air intake and the stock thermostat was replaced with a 160 degree one. Check engine light comes on and only code indicates secondary air injection sytem malfunction. Apparently the air pump has been completely disconnected and removed which is what is causing the light to come on. I've been told I can have the chip re-tuned so that this doesn't happen which I may do sometime but for now that isnt my biggest issue. When I fist start the car there is a pecking noise that is very noticeable but goes away after awhile. After a google search and reading about some other ppls experience my best guess is piston slap. The only symptoms I notice that are different in my situation vs others with piston slap is that they seem to indicate that the noise goes away rather quickly, like after a min or 2 of warming up whereas mine takes a bit longer. After first start up of the day I can drive about 1.5 miles down the road to the gas station and still hear the pecking if I roll down the windows or open the door, but then if I drive another cpl miles and stop the sound is completely gone. Any ideas of what this might be? If it is piston slap what if anything can be done about it? I just joined this forum and this is my first post, any input or suggestions will be greatly appreciated, thanks!

 

You'll probably get better help posting this in the LS1 forum instead of the LT1 forum.

 

Thanks, I reposted in the Ls1 forum.