thanks for the input. i've been wanting to turn the pump up but i was afriad it was going to make the mpg drop even more. i guess i'll have to drive the v8 dokota and start to make the ctd a toy.

 

I would do the following, in no certain order, but get it done as soon as weather permits.

-Change ALL fluids and filters- from the antifreeze to the rear diff and all in between. Friction from old oil and fluids can drop you up to .5mpg. Dont have to go synthetic (esp if you have some seepage), but a good quality petro oil will do well.
-get a pyrometer and boost gauge in there. Tach my also help diagnose what the tranny is doing as well. If you gain 300rpm to keep speed up hills, you have tranny issues.
-Valve adjustment. I have had that make a 2-3mpg difference, no other changes. You'd be up to 16.5mpg by that alone.
-Check lift pump output pressure. For a stock engine, book calls for 3psi minimum at WOT (loaded, not in Park in the driveway). I like to see 5psi on my uprated rig.
-If that fails, it may be time to get the injectors pop tested for pressure and atomization. I have gained up to 4mpg by getting them back to spec. Your sticks flow enough fuel that most upgrades (short of custom EDMs) will net little to no improvement in power.
-if you do asjust your timing, go a little at a time. The 89-90s start out with more advance than the later engines, but they all like about the same advance for maximum MPGs and power (1.5-1.6mm @ TDC). DOnt rely on the timing pin for checking the timing.

Daniel