Engine idle

[paul dorz]

I've got problem with car when caught in traffic.
When on longish journeys if I then get caught in slow moving traffic the revs increase to 2,500.
Any ideas as to what might cause it?
:wall:

[welshone]

I've got problem with car when caught in traffic.
When on longish journeys if I then get caught in slow moving traffic the revs increase to 2,500.
Any ideas as to what might cause it?
:wall:

What throttle body do you have? Alloy or black plastic??

The Black plastic one is prone to sticking so might be time to upgrade to a alloy one. If you already have the alloy one then dab a bit of oil on the cable ends as it might be getting dry and sticking in the cable cover.

[paul dorz]

I've got alloy throttle body and I oil it regularly. Used to have plastic one but they all seem to stick,my revs build up gradually and only clears up if get going again.cheers.

[welshone]

have you tried cleaning inside your throttle body there maybe something obstructing the butterfly valve inside.

[Fast Alan]

I would think you have an air leak,most likely on the inlet manifold gasket/s,I had the same thing happen on a Coupe,changed the throttle body and no difference then found the gasket between the head and the manifold was leaking

[paul dorz]

I'll pop the throttle of tomorrow and give it a good clean, is brake cleaner ok?

[welshone]

I'll pop the throttle of tomorrow and give it a good clean, is brake cleaner ok?

That's perfect, but i think Alan is more right on this one as it's only happening on long journeys this will effect the gasket. It's a fairly simple job to do.

[paul dorz]

Allan is there an easy way to check inlet manifold gasket for leaks.

[welshone]

windless day, engine running, bonnet up and blow cigarette smoke at the manifold and see if it sucks the smoke in ;)

[paul dorz]

:thankyou: That's two jobs for tomorrow.

[Fast Alan]

As he says ,you might find you need to get it up to temperature as the leak will be small and effecting it when the cars hot and you could spray around all the joints from the rear of the throttle body to the head and listen for a difference

[paul dorz]

Cheers Allan I'll be glad to get to bottom of this I've just finished cleaning idle air control valve quit a lot of carbon buildup but I've done all usual checks now so I'll have a look tomorrow:thankyou:

[600t16]

leaky manifold , had same problem on me t16.