Technical Very fast idle speed

[punto24]

I have a 2002, X reg, 1200cc Punto ELX 8V.

Just recently, and only occasionally, the idle speed refuses to drop below 2-3000 RPM when the throttle is released. Sometimes the idle speed continues creeping up to 4-5000 RPM and the only thing to do is to cut the engine.

This is worrying enough to a hairy old bloke like me but to my son and daughter who are new to driving the experience is very alarming.

Last year I had new coils and leads fitted as part of some other work.

What suggestions, causes and general good gen can all you helpful forum readers come up with?

 

[ST60SX]

Does the pedal get stuck at all? Check the throttle cable isn't sticking and holding the throttle open.

Other causes can be vacuum leak somewhere, although this would need to be intermittent and very large and therefore unlikely I would say.

I would suspect the ICV (idle control valve), try removing it and giving it a clean. Clean the throttle body and breather hose as well.

 

[MikeSalt]

ICV would be my first place to look too.

 

[D4nny8oy]

Might need the modified Throttle Position Sensor if it's not already had one in the past.

 

[S Denison]

Our '04 Punto 1.2 8V has the same problem.
It will idle at the correct speed, then occassionally for no apparent reason just start to rev at around 2500 rpm for several minutes, then drop back to normal.
It's most obvious in slow traffic, but have noticed it when driving on B roads too.
The throttle cable is free with the butterfly valve being closed during a phase of the fast idle.
I've tried several throttle valves (I think I'm on number 3 now) off scrappers with very little change, so is it likely they all have the same fault on the throttle position sensor - assuming it is mounted in the throttle body ?
I tried resetting the ecu following posts from this site with no effect.
Where do I get one of the modified sensors from - is it a Fiat part ?
Should I try changing the ECU this time ?
Regards
Simon

 

[s and b]

make sure the breather pipe is securely connected and no splits and fits on the airbox snugly and airbox fastened to injun properly
2 bolts
1 spring

 

[mart1986]

i had this problem every time i pressed the clutch revs shot up i stalled the car 3 times in a row lmao what was causing it was the electric block to the control idle valve was coming loose

 

[fingers99]

Likely causes are (not necessarily in this order):

Sticky or overtight throttle cable (check that the butterfly returns to closed -- there should be plenty of slack)
Air leak (as the froggy one suggests)
Idle Control Valve issue (electrical or filth)
Some t*at buggering about with the throttle stop.