diff --git a/feeds_tamper.module b/feeds_tamper.module
index ecbc2bc..45334de 100644
--- a/feeds_tamper.module
+++ b/feeds_tamper.module
@@ -24,55 +24,45 @@ function feeds_tamper_feeds_after_parse(FeedsSource $source, FeedsParserResult $
     return;
   }
 
-  $csv = FALSE;
-  if (get_class($source->importer->parser) == 'FeedsCSVParser') {
-    $csv = TRUE;
-  }
-
-  // Look for any "Blank source" mappings as those will be treated specially.
-  $mappings = $source->importer->processor->config['mappings'];
-  $blank_mappings = array();
-
-  foreach ($importer_instances as $element_key => $instance) {
-    if (strpos($element_key, 'Blank source ') === 0) {
-      $blank_mappings[] = $element_key;
-    }
-    // Special case for FeedsCSVParser.
-    elseif ($csv) {
-      unset($importer_instances[$element_key]);
-      $importer_instances[drupal_strtolower($element_key)] = $instance;
-    }
+  $parser = $source->importer->parser;
+  $is_csv = FALSE;
+  if (get_class($parser) == 'FeedsCSVParser') {
+    $is_csv = TRUE;
   }
 
   $plugins = feeds_tamper_get_plugins();
-  foreach ($result->items as $item_key => &$item) {
-    // Add the blank sources to the item.
-    foreach ($blank_mappings as $blank) {
-      $item[$blank] = '';
-    }
+  foreach ($result->items as $item_key => $item) {
+    // Manually advance the current_item key since we can't use shiftItem().
+    $result->current_item = $item;
+
     foreach ($importer_instances as $element_key => $instances) {
-      if (isset($item[$element_key])) {
-        foreach ($instances as $instance) {
-          // If the item was unset by previous plugin, jump ahead.
-          if (!isset($result->items[$item_key])) {
-            break 2;
-          }
+      if ($is_csv) {
+        $element_key = drupal_strtolower($element_key);
+      }
 
-          $plugin = $plugins[$instance->plugin_id];
-          $is_array = is_array($item[$element_key]);
+      // Plugins assume that everything lives in the item array.
+      $result->items[$item_key][$element_key] = $parser->getSourceElement($source, $result, $element_key);
+      $is_array = is_array($result->items[$item_key][$element_key]);
 
-          if ($is_array && $plugin['multi'] == 'loop') {
-            foreach ($item[$element_key] as &$i) {
-              $plugin['callback']($result, $item_key, $element_key, $i, $instance->settings, $source);
-            }
-          }
-          elseif ($is_array && $plugin['multi'] == 'direct') {
-            $plugin['callback']($result, $item_key, $element_key, $item[$element_key], $instance->settings, $source);
-          }
-          elseif (!$is_array && $plugin['single'] != 'skip') {
-            $plugin['callback']($result, $item_key, $element_key, $item[$element_key], $instance->settings, $source);
+      foreach ($instances as $instance) {
+        // If the item was unset by previous plugin, jump ahead.
+        if (!isset($result->items[$item_key])) {
+          break 2;
+        }
+
+        $plugin = $plugins[$instance->plugin_id];
+
+        if ($is_array && $plugin['multi'] == 'loop') {
+          foreach ($result->items[$item_key][$element_key] as &$i) {
+            $plugin['callback']($result, $item_key, $element_key, $i, $instance->settings, $source);
           }
         }
+        elseif ($is_array && $plugin['multi'] == 'direct') {
+          $plugin['callback']($result, $item_key, $element_key, $result->items[$item_key][$element_key], $instance->settings, $source);
+        }
+        elseif (!$is_array && $plugin['single'] != 'skip') {
+          $plugin['callback']($result, $item_key, $element_key, $result->items[$item_key][$element_key], $instance->settings, $source);
+        }
       }
     }
   }