Visit a wreckers and get a good replacement, blow out with compressed air then clean with carb cleaner or similar... Fuel filter and worse gas mileage, sounds silly as... Change the fuel filter, if the car hasn't had an air filter change I'd advise doing that too... A bad ECU could be the cause of really bad consumption (too rich) but I think you would see that with black smoke out the tailpipesorry for the late response...i have been really busy as of late. no gas leaks anywhere, it just seems to get the worst gas mileage ever, but that is expected with older vehicles. i have looked at the fuel filter and the lines and visually they look like they could need to be replaced, but replacing fuel lines can be very expensive ( almost more than the vehicle ).
How bad is bad? with a N/A 16v yo should be getting 25-30mpg I think approx depending on how you drive
When you drive your car do you have a fuelly smell or anything? How long has it been since you've replaced your O2 sensor?