av8or1:
Anyway, this doesn't address the issue I raised.
Which was impossible until you clarified how the readings had to be scaled. Despite what you believe, I am not able to read your mind nor am I able to remotely divine datasheets.
No big deal though, I'll just go with what I have 'cause it makes sense.
Don't. It's wrong.
Try this...
int PSI = (((analogRead(0) - 102) * 400L) + 819L) / 1638L
I assume to-the-nearest PSI is acceptable.