My service engine light came on coming home from work and every time I try to read the codes with EvoScan it gives me different answers. Finally it gave me all of the codes at once:

Updated: 19:01:46
Vehicle speed sensor
Barometric pressure sensor
Knock sensor
EGR sensor

The only one that throws a red flag to me is the knock sensor which is odd because i am not knocking at all according to my logs. The rest...I dunno...any ideas about what would cause them? I was having an overboost which was since resolved and the codes were cleared. Are these just stored? If so, how to rid myself of a pesky stored code? I tried using Scan Tech II to pull and clear the codes but for some reason it keeps timing out even though I have it set to the JEFF Protocol and correct com port.

Assistance please?