This randomized phase II trial is studying giving bevacizumab and cetuximab together with irinotecan to see how well it works compared to giving bevacizumab and cetuximab alone in treating patients with irinotecan-refractory metastatic colorectal cancer. Monoclonal antibodies such as cetuximab and bevacizumab can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or deliver tumor -killing substances to them. Drugs used in chemotherapy, such as irinotecan, also work in different ways to kill tumor cells or stop them from growing. Giving cetuximab and bevacizumab together with irinotecan may improve the ability to block tumor growth.