I have a 98 corvette, auto, and when it is cold there is a ticking sound. However, when it warms up after about 5 miles it goes away. When cold, it also gets louder as I step on the gas and gets quieter as I release on the gas. A mechanic at a local repair shop couldn't find the problem. Any Ideas?

I believe that you have a weak lifter. It's not pumping up with the cold oil. After everything warms up it is pumping up and closing the gap that is causing the "Tap".

That ticking turned out to be compressor belt noise. It was a fairly new belt and I still can't figure out why it was making noise. Loud too. I put silicone lube on the belt and the noise disappeared almost immediately. And hasn't come back. It is a Dayco belt.

Glad ya got it figured out.
That's a new one on me, I'll try to remember it.