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Originally Posted by vid6639  So what's the difference between DFCO and IAC valve. their functions seems similar. |
No their functions are different. While the DFCO cuts off fuel at no throttle conditions and injects fuel at a particular RPM (say at idle or just near to idle) after the cut-off time, the IAC valve helps is maintaining a constant idle (say 750 in case of idle and 1000 incase of idle in gear). The basic function of the IAC valve is to prevent the car from going off at no throttle position.
However a deeper dig into this jerking problem threw up another possibility. Ignition problem, due to spark plug wire arcing to the engine ground or a faulty spark plug setting. This diagnosis only gets worse. My baleno too jerks a bit too much in 1st and 2nd gears only. Sounded more like a fuel pump problem, though will check for the ignition timing thing and revert back.