There are 11 non random tests with a few "big" (order of 10^6) numbers and 10 random ones without "big" numbers. I don't see the need for a sort. If you time out maybe it's because Codewars is too busy or because your algorithm is too slow, I am unable to know...

For C#: How many test cases are there? If I don't do a sort at the end, I fail the random tests and pass test 1, but it ends there. If I put in a sort at the end I pass the random tests and test 1, but then it says it timed out (process took longer than 6000 microseconds). I am wondering if it is passing the tests and something else is wrong or if there are more tests. (If I comment out the sort after running the tests, it still times out, if I do a refresh it goes back to finishing but failing the random test.)

only one pass through the data, good job

This is similar to mine, and this is the only (other) one I found that actually uses only one pass through the data (max, sum, sort and variations thereof all do a pass)