Do not pay attention to the knock sensor. That is a waste of money repair.
Your problem is very likely to be the CAM position sensor in the distributor. To fix it, replace the distributor and recheck timing. If the van does not start at all now, the unlikely problem could be the ECM (engine computer). I have mine being repaired in Florida. My van does not start at all. I spent one month doing all kind of testing to confirm it was a computer problem.
The speed sensor is a good repair because the signal is also used by the transmission computer.