Water in Delta P sensor ....

[East Coast ISX]

Hello all, new to the forum and trucker life as well, currently own a 13 W900 with a Cm2250 570k miles, just did a map sensor and delta P sensor, the map sensor was filthy, the delta P as well but it also had water inside....any reason for this ? In desperate need for better MPG, currently not seeing more tha 5.6 mpg hauling 8,000 lbs.