Hi my Silverado 2013 1 start all the lights come on but it won't start turn on sometimes sometimes doesn't now I got this new thing on my - that say oil engine pressure low I replace the oil sending unit saying the same thing it runs fine it sounds fine any idea was wrong with it

 

Does your oil pressure gauge show low/no pressure? If your sure about good oil circulation, it could be the oil pressure sensor.

 

Did you check the oil level? When is the last time the oil and filter were changed? You can try a mechanical oil gauge to see if it really is low oil pressure.