revving itself constantly! failed mot emmisions

[vicj69]

ive got a T reg saxo 1.1i and it failed its mot on the co2 emissions.
the car is now constantly revving which is very embrasing when at lights and people think u are an idiot or are wanting to race them!
we replaced the lambda (o2) sensor and that didnt get rid of the problem.
i have done some research on the net and some people say its the coolant temperature sensor - which i have no ordered and am hoping this will work.
there is a fuel smell and its running rich, before the car started revving itself constantly the exhaust had a popping noise/sensation.
its as if someone keeps putting their foot on the accelarator every second or two.
any ideas what this could be?:bored:

[furiosteve]

I had a similar problem caused by a split in one of the hoses on top of the engine that feeds into the throttle. I replaced the split hose and all was well :)

Hope your's is as easy.

Steve

[vicj69]

Bump!
any more idea peeps? please help

[AlexB]

could be the stepper motor also know as the idle controll valve

or a map sensor (if the 1.1 has one)

[Rob]

leaky head gasket?