Mmmm you'd have to google this for more info, but my vague recollection from working on my 1989 Buick in high school is, unplugging certain sensors can force the engine to operate "blind" for example adding more fuel that otherwise would be needed just in case. So you might temporarily make your engine problem better, but your fuel economy will surely get worse and you will breathing a lot more NOx than is healthy. I don't think you can damage the car in the short run, but it's possible you might get deposits built up over time - it's smart to fix it sooner or later, and if your country has emissions requirements, the yearly check will force you to do it. And, the good news is that if you A/B test that sensor you can be pretty confident it's faulty, so you can just go buy a new one and pop it on yourself ...

 

i see, I did try test and replace the EGR i borrowed from my friend's car (same GD1 1.3 Fit) but unfortunately the problem still exists (noise and slight jerk). Is there Any way to check if which sensor is malfunctioning ? (knock sensor, O2 sensor, etc.) Since I don't get any CEL at all when EGR is plugged in.