Poor Gas mileage please help

I have a 94 GMC Extcab 350 TBI.. and it get very poor mileage..Please if you have any idea's to help get the mileage beter plaese fill me in..

Windowjamber  

theres a few possibles

 a bad 02 senor maybe

timing could be off or plugs and wires

dirty injectors in the throttle body             PROLLY

or just your foot is too heavy

there the ones i can think of right now

good luck

Are you running the stock tire size?

How many miles on the engine?

Any mods? (as simple as an aftermarket air cleaner)

When was the last time tranny and diff fluids were changed?

PCV valve ok? Air filter clean?

When was the last time the fuel filter was changed? 

Fuel injectors spraying mist or dripping fuel?

check engine light ever come on?

What are you actually getting for gas mileage? (an actual MPG number)

I have a 92 k1500 with 130,000mi on it, several bolt on engine mods on the original 5.0L, 235/8516 tires, and my MPG ranges from 16-25 on regualr fuel depending type of driving and outside temp. I get about 12mpg towing my s15 (the bummer) on premium.

Thanks for the heads up man.. I'll look into all of that some i have already  but you listed a few i did not think of  

Besides a basic tune up I would suggest some fuel injector cleaner ( you know, that stuff in a bottle that you add to your gas tank) you'd be suprised at the difference you'll experience from a bottle or two of this swill.  If this doesn't help you should buy a bicycle.