I have a corolla GLI (Pak assembled) 99 AT. It does about 120 KM on 55 pounds cylinder in city. is it OK? But the problem is that on patrol it does only 10 KM/L on highway. A mechanic asked me to replace the injectors with that of VITZ. but one my friends is of the opinion that it will ultimately weaken the engine.

Any Expert Opinion?

Thanks