OUTER JOIN IS SLOW

I have been running pieces of my PL function by hand and I have found
that the following queries work by themselves taking less than a second
to execute.

getDateRange"('12/1/2005','12/1/2006') <- simply generates a date
list. Doesn't even access a table

SELECT * FROM mutualfd_weekday_qbid WHERE cusip='92193920' AND pkey >=
'12/15/2005' AND pkey <= '12/15/2006';

But when combined as below it takes 10 seconds to execute.

SELECT d1 as date, d2.data as data FROM
"getDateRange"('12/1/2005','12/1/2006') d1 FULL OUTER JOIN (SELECT *
FROM mutualfd_weekday_qbid WHERE cusip='92193920' AND pkey >=
'12/15/2005' AND pkey <= '12/15/2006') d2 ON d1=d2.pkey;

Do I need to increase the work_mem or is this possible still a ANALYZE
issue?

Benjamin