punto problems

[andyhughes1199]

Hi
I have a Punto 1.2 8v 2005.
The car when idleing at 800 rpm suddenly drops to 500 rpm, and keeps doing it. When driving especially accelerating it feels like its miss firing it judders and struggles upto speed when upto speed it seems fine.
I have changed the coils, spark plugs and HT leads, cleaned airfilter but problem persists. I have also put some redex in to no avail.
Any suggestions would be greatly recieved.
I have had suggested that i reset the ECU ? by taking the battery cables off ? if i do this will i lose radio and central locking codes ?
How long would i need to take them off for ?
Thanks
Andy

 

[andyhughes1199]

I forgot to say that the car has been on a diagnostic machine but came back with no faults.
When i phone Fiat all they want to do is put it on for another diagnostic check, but i cant see the point in that, when ive already paid for one which found no faults, i think they just want to charge me again for it.
Andy

 

[^neo^]

if the revs are hunting, it's usually a sign that the coolant temp sensor is shot

 

[andyhughes1199]

what is a coolant temp sender ?

 

[Stivino]

http://tinyurl.com/yzy6my2

 

[Nitronick]

Hi
I have had suggested that i reset the ECU ? by taking the battery cables off ? if i do this will i lose radio and central locking codes ?
How long would i need to take them off for ?
Thanks
Andy

Radio Code may be lost but CDL wont be affected.

Just disconnect the battery for 20 mins then take it for a drive using every gear.

Most likley cause is an Idle speed Valve of some discription. Should need removing and given a quick clean with carb cleaner.

With respect to previous poster I seriously doubt it will be the coolant temp sensor.

 

[Stivino]

The previous post was mine. I didn't suggest there was anything wrong with the coolant temp sensor. I answered the OP's question in his latest post, which was; what is a coolant temp sender ?

Given that your car is only 5 years old, I'd imagine the radio code shouldn't be too far away. Have you tried all the usual places? It might not be a coded radio, it might be linked in with the ign key. (I've done one of those radios and it just escapes me whether or not it is a coded one)