I need to replace the oil press sensor on it. i cant find a diagram to let me know where its at. all the diagrams online are different. can someone please help to let me know where its at. Thank you for your help.

 

there is a section for chevy express, you posted in the 'general' section...
i dont know the answer but i bet someone in the express section does...

 

When you do post in the van section, you might want to mention which engine you have (There are several sizes, each with their own diagram.), and the symptoms you're experiencing.