Like many of you I have been concerned about my vette’s cold engine noises. I have read all of the posts about piston slap and listened to sound clips and still can’t decide if my car has this malady. Mine sounds more like poorly adjusted solid lifters, which vette's don't have.

So I decided to diagnose my engine noises. First, I bought an auto stethoscope. For those that are unfamiliar with these they look like a medical stethoscope, except that they have a metal probe sticking out from the part that your doctor normally puts on your chest. These are great devices for locating engine noise, including piston slap. They are inexpensive. I paid $20 from my local NAPA store, but they can be had for under $10 on the web.

Next, I took off the plastic valve cove shrouds and started my car. I noticed that my engine sounded somewhat quieter. This surprised me. However, I could still hear quite a bit of noise. I probed the valve covers and the block with the stethoscope to locate the engine noise. Everything sounded fine. Finally I put the probe on a fuel rail and a fuel injector and wow are they noisy! I have never heard anything that loud from any other fuel injected car that I have owned!

So my engines noise is coming from my fuel injectors. When I reinstalled the plastic valve cover shrouds the noise seems much louder! I think the plastic shrouds amplify the noise because they cover the injectors and partially snap on the fuel rails! I feel much relieved since this is normal noise. I highly recommend purchasing one of these stethoscopes. They really work!

 

Thats good info, I don't think that injector noise would have been at the top of my mental checklist of possibilities.
I'm also a pilot and it's funny how the plane's engine always seems to make the strangest noises when you're flying over water or other unforgiving terrain. Alot has to do with what the mind wants to hear (or doesn't want to hear)