Low Idle whilst stopped in Drive

[DomTurner]

I have recently noticed that when I am stopped in Drive with my foot on the brake, the car will idle at around 450-500rpm and I can feel a vibration through the steering wheel. When releasing the brake pedal, the car is sluggish to move meaning I am having to use the accelerator to move off. Before this the car would idle at around 550-600rpm in Drive and got up to at least 5mph without having to press the accelerator at all.

 

In Park and Neutral the RPM seems to be as it was before at around 750rpm. I have not really tested it in Reverse.


I was thinking it was perhaps throttle body/MAF sensor related but wanted to see if anyone had any other ideas.

[ColinBarber]

Throttle body cleaning is normally the first thing to check/perform when you have an idle issue but worth making sure vacuum hoses are in good condition and that you can't hear any air leaks. Coolant temperature sensors can cause idle issues, but that is more related to the LS400 rather than LS430.

If you have access to a diagnostic tool that can show you rpm/engine temp/fuel trims etc it would help eliminate a faulty sensor, if not start by cleaning the throttle body and MAF sensor.