Tuning Help-Urgent

[portal]

Folks,
I'm trying to execute a simple qry like this takes 35 mins

1.select  * from building_info where bld_seq_id=21261023;
120 rows selected.
Execution Plan
----------------------------------------------------------
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=5 Card=1 Bytes=37)
   1    0   TABLE ACCESS (BY GLOBAL INDEX ROWID) OF 'BUILDING_INFO' (Cost=5 Card=1 Bytes=37)
   2    1     INDEX (RANGE SCAN) OF 'BD_SEQ_ID' (NON-UNIQUE) (Cost=4 Card=1)
Statistics
----------------------------------------------------------
          1  recursive calls
          1  db block gets
    6123550  consistent gets
    6058079  physical reads
       8144  redo size
       8121  bytes sent via SQL*Net to client
        589  bytes received via SQL*Net from client
          9  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
        120  rows processed

When I pass a hint of the same Index , it returns in seconds.All the statistics are current, also I increased arraysize to 2000 still consistent gets/pIO is same. Give me some suggestions guys.Oracle 9i on Windows,Table Partitioned and Global partitioned Index.
Thanks