I've had bi-lateral meniscus repair a few years ago, now my left knee is popping and giving out when I walk 2 miles? Could I need another repair?

Another tear likely. Knee popping and a sense of giving way in a knee with a prior history of meniscal repair is strongly suggestive of a recurrent meniscal tear or overlying cartilage lesion. Besides obtaining a recent weight bearing knee x-rays series to assess for joint space narrowing and arthritis, an MRI will likely be ordered.