two ?'s tach, and fuel system fault codes

[hakogen]

i've got an 01 s-10, I4, 5 speed... 75k miles, ALL highway...
1.) I dont have a tachometer, and if i get an original factory instrument cluster, with the tach, can i just stick it in? Is there a sensor somewhere in the driveline that is going unused that my tach could hook into, or is this way more trouble than its worth?

2.) My MIL came on a few months ago, and at the time I was able to afford a OBD2 diagnostic tool. The tool is telling me P0178, and P0179. After a reference to the manual, I learned that the codes mean 'Fuel Compensation Sensor Circuit Low/High Input, respectively.' The truck still runs well, and I'm a penniless college kid so I haven't been chomping at the bit to get it fixed. However with summer coming, and being home from college, I'll probably be doing a lot more driving. Could this be a fuel filter that needs replacing, or is there something far more sinister at work here?

Any input at all would help. Thanks guys.