Sorry DD /forums/images/graemlins/blush.gif I thought because you responded to to my post you were talking about me LOL.
As for getting better milage:
Do a through tune up. Plugs wires cap rotor fuel filter. Check all vacume lines for breaks or holes.
with the TBI you can set the base timing a few degrees over 0 without problems and get a little better performance. Do not excede 4 degrees BTDC or it may ping or throw codes.
Get a free flowing exhaust. if you dont have smog tests loose the cat and plumb single 3" pipe with a good muffler all the way back. Headers wont help much with gas milage and are a needles expense if gas milage is your goal.
Check out this stuff:
http://www.turbocity.com/TBIPowerMain.htm
Get the air flow enhancer it works its worth the 40 bucks.
The TBI spacer may also help because it builds torque
A better coil like the MSD blaster helps MSD makes a direct plug in coil for TBI trucks.. Then You can open up the plug gap some. I run my plugs at .050" But it best to experment to find out what works best for your rig.
Use synthetic lubes in engine and drive train.
Check air inflation in your tires. The more pressure you can run without wear problems the better milage you will get.
The best mods for fuel milage are ones that build low end torque. the less you have to press the gas pedal to move your truck. The less gas you will use
I run all the mods I have listed on my TBI 350 and get 18 mpg at 75mph on the freeway I have got as high as 20 but I Cant Drive 55 mph
I get 15 mpg average around town if i can keep my foot out of it.