rebuilt computer (did it myself and if i had messed up im sure it wouldnt be running at all)
Not necessarily.
If you have any way to get a known good ECM and swap it in, then I'd try that.
Was it not running at all, before you fixed the ECM?
What all did you do to fix the ECM? Just replace the caps? Generally, there are also some bad traces on the ECM board, because of the bad caps leaking onto the board. So these have to be found and fixed too, or you will still have running issues.