Problems with the computer(excesive fuel consuption)

[jose]

Hi I got a 87 sentra 1.6 (the injector is like a carburator), this car has an excesive fuel comsuption, at 2,000 rpm the car fouled a spark and not the same spark everytime, I changed the ignition and the oxigen sensor I need your help in finding the problem.

Thanks

[NM50]

Replace the O-rings on the injectors.Use vaseline on them to keep them from tearing.