diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 35dfbcb12f..2f7a08e4dd 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -723,16 +723,8 @@ class Query(object):
         opts = self.model._meta
         alias = self.join((None, opts.db_table, None, None))
 
-        try:
-            field, target, unused, join_list = self.setup_joins(parts, opts,
-                    alias, (connector == AND))
-        except TypeError, e:
-            if len(parts) != 1 or parts[0] not in self.extra_select:
-                raise e
-            # Filtering on some alias from extra(select=...)
-            self.where.add([None, parts[0], None, lookup_type, value],
-                    connector)
-            return
+        field, target, unused, join_list, = self.setup_joins(parts, opts,
+                alias, (connector == AND))
         col = target.column
         alias = join_list[-1][-1]
 
diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py
index 97e6c38e6b..d361916953 100644
--- a/django/db/models/sql/where.py
+++ b/django/db/models/sql/where.py
@@ -5,7 +5,6 @@ import datetime
 
 from django.utils import tree
 from django.db import connection
-from django.db.models.fields import Field
 from datastructures import EmptyResultSet
 
 # Connection types
@@ -103,10 +102,7 @@ class WhereNode(tree.Node):
         else:
             format = '%s %s'
 
-        if field:
-            params = field.get_db_prep_lookup(lookup_type, value)
-        else:
-            params = Field().get_db_prep_lookup(lookup_type, value)
+        params = field.get_db_prep_lookup(lookup_type, value)
 
         if lookup_type in connection.operators:
             return (format % (field_sql,
diff --git a/tests/regressiontests/queries/models.py b/tests/regressiontests/queries/models.py
index e7e78e23cd..0404e9f9be 100644
--- a/tests/regressiontests/queries/models.py
+++ b/tests/regressiontests/queries/models.py
@@ -458,19 +458,11 @@ thus fail.)
 >>> Item.objects.extra(select=SortedDict(s), params=params).values('a','b')[0]
 {'a': u'one', 'b': u'two'}
 
-Bug #4002
-Attributes used in extra(select=...) are available for use in subsequent
-order_by() and filter() calls.
-
 # Order by the number of tags attached to an item.
 >>> l = Item.objects.extra(select={'count': 'select count(*) from queries_item_tags where queries_item_tags.item_id = queries_item.id'}).order_by('-count')
 >>> [o.count for o in l]
 [2, 2, 1, 0]
 
-# Filter those items that have exactly one tag attached.
->>> Item.objects.extra(select={'count': 'select count(*) from queries_item_tags where queries_item_tags.item_id = queries_item.id'}).filter(count=1)
-[<Item: four>]
-
 Bug #6154
 Multiple filter statements are joined using "AND" all the time.