President Obama’s $5 billion stimulus injection into a decades-old program to help lower energy bills for millions of low-income families by retrofitting their homes to improve efficiency has been plagued by cases of mismanagement, waste and fraud in several states. The most dramatic example can be found in Delaware, where “gross mismanagement and potential fraudulent activity” that federal auditors found last year could affect hundreds of homes, a senior administration official told FoxNews.com. The subsequent repairs and inspections reportedly will cost the state a significant chunk of the $7.5 million remaining from $13.7 million of stimulus it received in 2009.