I know what they mean, rail pressure sensor voltage too low and too high, but what's wrong? I took the Quadzilla out of the truck, all connections are correct. Could I have a bad rail sensor? Also my Quad rail gauge can't read the rail psi, it shows (----). Truck idles like crap, it is drivable but sounds terrible.

 

Possibly a failed sensor, poor connection ( Someone has said they can go on backwards? ) or broken wire somewhere.....did you t-tap the wire?

 

No, I used the plugs and I'm positive it is connected correctly. This is an all of a sudden problem, Quad has been on for a long time w/ no issues. Gauge goes in and out working, then quits, works, quits.......truck runs real bad. I'm hoping it's a bad sensor.

 

Not when you see the price.................................