gas problem anyone knows whats wrong?

i got a 95 civic but it has a grs motor in it, and its sucking up alota gas..anyone knows whats wrong....im not even getting 15 mile a gallon...could it be cause i got high compression piston?

I don't think high comp pistons alone will give you that bad of gas mileage. But whoever did the modding, may have set the engine to run rich to avoid detonation due to the high comp. You might also have a bad o2 sensor, map sensor, injector(s), spark plug(s), distributor cap, etc. Does your exhaust smell like gasoline? Does the car run well? You need to give more information, and do some investigation, before people here can help you more.

yea my pipe smells like gas when its running....

Any other mods like a fuel pressure regulator, or anything like that?

Check your spark plug wires, distributor cap, and rotor for cracks, or any sign of damage. Pull out your spark plugs and see what they look like. If they all look good, check each plug individually to see if it sparks when you turn the motor over. Check your ECU for trouble codes. That may give a clue where to start. Do you have any of those map sensor mods sold on ebay? Those usually cause the engine to run rich. From there, you can start checking the sensors that I mentioned above. If you buy a Helm's manual, it has good diagnostics, and info on exactly how each sensor show perform. It'll be the best $60 you ever spent, if you intend to maintain your car yourself.