Hi.

I have a 2004 Fiat Punto. Im having a problem where sometimes i start the engine. The rev counters seem to be reving up and down between 500 to 1200 revs. This seem to happen more often on cold mornings. Once i start driving the car. Im reving the car up to change gear and it is juddering along and not running smoothly. Especially in 2nd gear. I bring my foot of the clutch when i have changed gear and it judders along the road until i change to 3rd. Once Ive been driving for i would say about 10 15 mins the problems seems to go. I dunno if this has something to do with the engine being warmer so the problem is less apparent. But im not too sure.

Can anybody help????

could be the lambda sensor

chances are is it is logging a fault code so get it put on a diagnostic machine

you can do it yourself if you buy the right cabel and download the free fiatECUscan software

there is a guide in the punto guides section on how to do it yourself

Thanks.

My exhuast did come off a few weeks a go so this could be the reason why??

GJL said:

Thanks.

My exhuast did come off a few weeks a go so this could be the reason why??

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could be

what part of the exhuast came off ?

how was it repaired?

The whole exhuast really both the exhuast and exhuast pipe just burnt off.

Got both replaced and the brackets. Not really sure how it was repaired just know i got a new one

Check the Battery teminals are on nice and tight - and cant move
poor connection can make the car Rev up to make the alternator work to sustain running

A weak battery can short out internally - making the car panic and rev to maintain power

Sticking Throttle Body Valve - makes the car stick open and closed - cheap to sort as well

I dont think an exhaust been replaced can make a difference, but its better once warm
Could be
damp plugs - drying out = power restored
A Clogged Injector - Heat might allow fuel to flow again
HT is shorting via the body instead of the plug
Lamba sensors - Dont work when cold, so once it gets upto temperature it kicks in and controls fuel, so i dont believe that it'll be them

Ziggy

could well be lambda sensor but the cheapest way to tell will be get the codes read

jip0 said:

could well be lambda sensor but the cheapest way to tell will be get the codes read

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Nope.. cheapest way to test the lambda sensors is to unclip them, will work ok without them connected.

paul12345 said:

Nope.. cheapest way to test the lambda sensors is to unclip them, will work ok without them connected.

Click to expand...

Cheers

Where will i find the lambda sensor and how do i unclip them??

paul12345 said:

Nope.. cheapest way to test the lambda sensors is to unclip them, will work ok without them connected.

Click to expand...

eml light should come on without lambda sensors

GJL said:

Cheers

Where will i find the lambda sensor and how do i unclip them??

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Theres 2 on the manifold ones hiding behind the heatsheild and one higher up.. you should be able to follow the cable a few inch there will be a simple connector unclip one/both, it will log an eml error, but at least you can rule them out.