Lcd Gauge display for truck

I wanna make a lcd gauge display for my truck. I was looking at it for boost (pressure transducer), egt (thermocoupler), engine coolant temp (can't find out what kind of sensor but I think its a thermistor) and engine oil pressure(i need to buy this) Im quite new to the arduino system and i can learn code if need be.
I have a mega2560 r3 with a starterkit that comes with a breadboard and a bunch of stuff. I have looked around and found a couple of videos on how to wire a few of them. to be honest i would just be happy with a boost gauge right now. I have the pressure transducer
(https://www.amazon.com/gp/product/B00RCPDPRQ/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1)

I had it all wired up and tryed codeing it and it always read 2 psi when i had it one the breadboard. I haven't hooked it up to the truck yet cause I wanna have someone to look over my code to be sure it all looks good.

Im useing a 16,2 lcd and the pressure transducer in this prototype


#include <LiquidCrystal.h>
LiquidCrystal lcd(12,11,5,4,3,2);
int psival;
int Psipin = 0;

void setup() {
lcd.begin (16,2);
}

void loop() {
psival= analogRead(Psipin);
float y = ((psival/1024.0)*25);

lcd.print("PRESSURE = ");
lcd.setCursor(0,1);
lcd.print(y);
lcd.setCursor(5,1);
lcd.print("PSI");
delay (100);
lcd.clear();
}


anything will help

Thank you and sorry for the bad typing