My 2000 (Mark 2 1.2 8V) Punto has recently started to rev uncontrollably when the engine is warm. Generally this problem only occurs in neutral when changing down, but it is starting to affect the car in gear as well (it will happily maintain a speed when I have removed my foot from the accelerator). The revs seem to 'want' to be at around 3500rpm when in neutral.

I have taken my car to a garage who want to replace the throttle unit at a cost of £450, but they cannot be certain that it is the throttle potentiometer that is faulty. Is there anything else that could be causing this problem?


Thanks!

it sounds likely that they are correct have u checked the cable is free??
also maybe the crank case sensor needs checking

Only interested as I to have this problem. If you engage gear it controls the revving but as you say revs when changing. It is much better now since the weather has cooled.

My problem is that my garage will not even attempt to deal with as they cannot guarantee a cure and the Fiat Dealer service unit seems equally disinterested and has never heard of this sort of thing (they should read the Fiat Forum)

It has been through a diagnostic check but was all clear and they checked the wiring which was ok. I was thinking along the lines of the lamda sensor or the ECU (are these the same thing ?)

Any help in pointing a garage to the solution would be gratefully received. Am I doing any damage to the car by not fixing immediately ?

Check temperature sensor, my car behaved like that. One time I got stuck because I had to reverse and RPM wouldnt fall under 3500 so couldnt put the reverse in. Had to sit for 5-10 minutes before it behave . My car also had the injecotlight coming on and off.

If you change the temperature sensor, dont change the wrong, I did, there is one for the gauge and one for the ECU.

I've checked all the cables and had a diagnostic on the computer (which came back fine), so I'll have a look into the temperature sensor like you say. Are they easy to check / replace?

Same problem I think.

Originally had an intermittant starting problem, took it to the garage and they plugged it in and it said intermittant problems on the coils and the rev sensor. They suggested go away and come back when it happens again so that I avoid replacing the both as one may casue the other!?

THEN .... I noticed the wild dipping revs when in idle... it has even cut out a couple of time in traffic lights... This came out of nowhere!

I guess this is the rev sensor?? Only had the starting problem once since but no careful not to turn the key too quick (until the key light goes out) seems to work..... Is any of this linked? Usually when it doesn't start come back in 10 mins and then it's fine!

i have this exact same problem mate. i took it to the garage (research, nuneaton) and they said it was cos i had changed my dash to the 1 with the rev counter then they said that it was my ecu!! so im in the process of tryin 2 solve the probklem myself so i'd be grateful if u cood tell me wot solved ur problem.

also where abouts are the temp sensors??

cheers mate

Same on my 1.2 8v punto, garage said the pressure sensor had completely failed and steper motor faulty total cost 600 pound. good luck mate with yours.....

neil