One piece of that - lodged in the wrong spot, and you have the dreaded intermittent idle trouble. Since it's now-n-then that is my bet. Good clean w/ carb cleaner, (metering block especially), new base gasket and check all those holes for line up etc, then brake fluid, then lacquer thinner, then gun cleaner / acetone, then lots of air.
Only other times I've seen em do that intermittent thing:
1. Icing - not likely in this weather
2. Carb is not potty trained. So idle can be set very lean, but fuel sneaking past the gasket makes it richer = great idle. Then they warm up, the gasket decides to seal and stop peeing, and bingo, no more idle fuel cuz the screws are in too far. Again if this is a newer carb it is probably potty trained but potty training a Holley is like a puppy, it is not automatic U have to put in some effort.
Could also be an intermittent vac leak (cracked hose, carb gasket, etc).
Edit - both the body-to-throttlebody gasket and the carb-to-intake gasket can be intermittent culprits, check both for seal, lineup, and even the wrong gasket (BTDT too).
|This message has been edited by werbyford on Aug 27, 2012 12:01 PM|