Hi Bruce, On my '77 spider that happens when this little plastic pressure release valve near the trunk-mounted charcoal canister gets clogged up. Remove the valve, blow into it to clear it out, and then put it back. Should reduce if not eliminate the problem.
Not sure if the '74 set up is the same, but the symptoms sure sound familiar. Gets worse in hot weather. Chris Keen '77 spider, '79 gt SF, CA -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
