RPM at Drive position

[Ted]

Hi Guys,

My idle rpm at position N or P is around 725. When I apply D position when vehicle is in stationary,  rpm drops to 500 ( I do not feel considerable vibration).. Is it normal? Or should it be increased? 

All above are AC/Head lights etc in off condition.

Edited April 1, 2018 by Ted

[Rumesh88]

If the nominal idle RPM for our car without AC and headlights on is 800 then 725 is a tad bit low. When you shift to D there can be a slight drop in RPM but dropping from 725 to 500 is not quite normal. However in an EFI engine the idle RPM is decided by IACV assuming that the air cleaner is not clogged up, there are no vacuum leakages on inlet manifold side and that TPS, MAF, PCV are in order and the throttle is set at its factory set position. Usually there is no need to increase/adjust the idle speed by turning the idle screw from its original position.

[Ted]

As per my car manual idle should be within 650 to 750. No issue in TPS, MAP and ECU. Have to check for vaccum leaks... any idea on how to check ? Since O2 sensor adjusts when there is a vaccum leak it is very difficult to find it from rpm.

[MV-5]

12 minutes ago, Ted said:

As per my car manual idle should be within 650 to 750. No issue in TPS, MAP and ECU. Have to check for vaccum leaks... any idea on how to check ? Since O2 sensor adjusts when there is a vaccum leak it is very difficult to find it from rpm.

I think this is normal, in gear position D car is not idle. at gear D , Torque converter comes into action and vehicle is about to launch (somewhat similar to manual car launch point when you release the clutch pedal).