Shimming Fuel Pressure Regulator For Power
 

Shimming the fitting with a 3/16 spacer behind the spring in the fuel regulator. This is located on the right hand side of the fuel filter. You will see a 3/4 brass nut there. The spring is inside there. Shimming will raise the fuel pressure and often give you a worthwhile increase in power and no one that I can recall has reported higher fuel consumption.

Adding fuel pressure gauge:

Something else to do is to buy a fuel pressure gauge out of JEG's and just have it permanently attached all the time. You can unscrew the schrader valve and just screw in a fuel pressure gauge. You can buy them for up to 100-160 psi.

good info...thanks man

You should see a 10-20 psi increase in fuel but a word of advice. Be careful when removing the line, the spring will try to get a way from you and go easy on tightening the nut, it will strip the threads or snap the housing in half very easy. You can buy the housing separate from the water/fuel separator it you do overtighten but its around $70-$130 for that little jewel.

The problem we have on the DMax is even being able to get the darn FPRV off. It takes no less than a 20ft cheater, three men, and a baby. Thats the hard part, after that its a piece of cake.

you can also do the bb mod