I had my 73 crate engine timed...supposedly correct.. last fall. During the winter I garaged the Vette, changed the oil etc and started it up and drove it on clear days, just to keep the car from just sitting.
Last week I started the vette up and took it for a drive. The idle at a stop seemed o.k.. At times I would see a bit of cycling between 600 and 500 rpms. Then after a coffee break at a local shop, I took off and the vette seem to hesitate after I gave it gas. At the next light, the cycling of idle fell below 500 and the engine died. I started it up and took off. At power she runs good. Then after stopping at the gym for a workout, I started the vette and took off. She hesitated again and heard a mild carb backfire. On the way home I placed it in neutral at stop lights, in fear that she would die again. Once at home I let it idle in drive and watched the rpm. It was steady except for an occasional cycling up and down. I visually checked all of my vacuum lines, plug wires and distributer, and nothing looked out of the ordinary. Is there anything I may be missing. Why would it act like that. During my "limited" storage, I did keep the gas tank full and poured a bottle of heat in the tank to keep water out. Any ideas anyone?

 

Check for timing and carb adjustment.

 

Might be as simple as a fuel filter and this is easy to check. Might also check that the choke isn't in a bind somewhere.

 

Could also be a vaccum leak. Check the lines...

 

Thanks to all. I will check it out.