Engine revs don't reduce when backing off

[vs-lover]

Hi All,

I have a little issue that has been bugging me for a while and that is when driving at a set speed (lets say 60Kph) and you take your foot of the accelerator the engine wants to continue running at the same speed and not drop down straightaway, thus when braking it feels you are braking against what the engine want to do.

Anyone have any ideas, oh and btw it's not a binding cable either.

 

[Grimes]

I had a similar issue once but at idle. Turned out to be an oxy sensor causing the mixture to lean out little bit at running temps. Only found it after pulling the trends on a laptop. Not sure that fits your problem though. Something leaning the mix out or letting in some air like the IAC valve and seat, vacuum leak through the canister circuit might he worth looking at.

 

[07GTS]

yea IAC controls the airflow for idle and such so it may be worth looking at, or check the throttle cable make sure its returning to zero when released encase its sticking

 

[Draimond]

Idles ok tho?
Check for fault codes.
V6 or V8?
Check / clean throttle body and IAC.
+1 for vacuum leaks.

 

[vs-lover]

It's the V6. Must admit I've also been thinking along the lines of Vac leak or IAC issues.

Yes it idles ok, but does show signs of mild vibration

 

[BlackVXGTS]

Make sure you have 10-15mm of play in the throttle cable.

 

[vs-lover]

Make sure you have 10-15mm of play in the throttle cable.

View attachment 265797

thanks

 

[shane_3800]

Yea, I have had a few come backs, with throttle cables being too tight.
It's amazing how a few turns can fix the issue.

 

[vs-lover]

I'm going to loosen it tomorrow and see if that helps any.

 

[Lacksballs]

Isolate the booster line & check the throttle cable make sure it’s not binding. Spray brake clean along the inlet manifold gaskets up to the throttle body. Don’t forget the vacuum lines for the heater controls.