the injectors are obviously going out so I would get those fixed asap, I personally recomend Brent at Lincoln Diesel Services (Brent@LDS is his user name) and if you arent going to upgrade just get the bosch reman's they are around 1500 I believe, they will stand behind the warranty and exceed your expectations.
As far as your gauge cluster, your stepper motors are going out, it is very common. You can either get a new cluster and have your mileage changed over by a shop that does that, or if you can solder you can order some stepper motors off of amazon pretty cheap and even convert to some lights while you are in there!
Let us know how everything turns out.
And also, I am greatful to be the first to be able to welcome you to the forum! This is by far the best dmax forum!
Purchased 11/15/12: Totaled 7/24/14 2004 LB7 CCSB ATS 4000 Turbo
Diamond Eye 4 inch turbo back exhaust
Moog problem solver upper and lower ball joints
Blistein 5100's up front
H2's Michelin 265/70/17 E, Ranch hand front bumper. EFI LIVE by Kory Willis
Purchased parts awaiting install:
Special thanks to:Brent@LDS
, mrmanners@Synthetic Motorsports
, and Kory Willis@latuning
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