for a punto 03 plate 1.2 8v.

best to stay with a fiat original, or are there other brands which are ok to use?

cheers in advance.

scrappy

Who says its failed? Symptoms?

Garage is still checking, but I keep getting P0420 to go with my P0300.

I should know later what the damage is.

I have told them I am not replacing a CAT until the misfires are solved.

If he can't solve the mystery, I am afraid it's going to Fiat.

There is a Garage nearby that specialises in tuning and disagnotics I am tempted to take it there, but I am concerned about racking up costs at different independents who can't solve the issues.

Dont assume its the cat though a recent major head gasket failure or rich running for a long time can take them out.

Talk to the tuning bloke Puntos are nothing special but see if he's anti Fiat. Some still live in the 1970s.

Consistent missfires on the same cylinders point to the ECU coil driver fault (repairable).
Rough running and poor fuel consumption when hot point to Lambda.
Poor tickover - air leaks MAF/MAP

https://www.fiatforum.com/stilo/218285-fiat-stilo-p0420-fault-code.html
https://www.fiatforum.com/punto/72577-ecu-fault-p0300.html

The latter could have been an old battery loosened up by his crash (why do folks ignore handling issues) or maybe his cat got thumped.

Consistant mis-fires since a cambelt change (the guy insists the timing is ok) and the car runs smooth.

The guy said he messed with the crank sensor as it appeared lose.

I think it is running a little rich, but dash is reporting 46.7mpg.

I had decent acceleration, no lags etc.

The tuning/diag specialists I know are good from word of mouth, and the guy has spent sometime on the phone with me and offered alot of advice even though I havent had the car in there yet.

I am reluctant to send the car to fiat as they said there rates are £85 per hr, and to check re-do the timing is 2hrs+ according to them, and I am far to inept to do the work.

Could be a faulty crank sensor they dont like being messed with as they get older and cam belt jobs do seem to upset them.

misfires often kill cats because of all the unburnt fuel going through, so if it has gone and you fit another with out fixing misfires, its just going to kill the new cat too.

have you used the guide to check ecu?

ECU is getting checked this Saturday.

I get the misfire reports at around 55-65mph (engine lights flash) but it's not a exact science, sometimes its fine, but the car doesn't feel like it's misfiring.

After the codes have been re-set I can get 2-4 days driving with no faults then bam.

I was worried about the CAT as I get the P0420 which is that CAT threshold warning.

And yup for sure there is no way a new CAT's going on until the mis-fire or is throwing up the mis-fire fault is diagnosed and sorted.

Edit: I never get the faults on start up, it's after a sustained run and engine is up to temp.

Missfires have to be pretty serious to blow the catalyst, but never a good thing. I suspect its the crank sensor with the cat warnings coming up as symptoms

WhiteSei said:

Missfires have to be pretty serious to blow the catalyst, but never a good thing. I suspect its the crank sensor with the cat warnings coming up as symptoms

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3 miles killed mine, could see bits of hot cat coming out the back glowing red

Ouch !!!

diagnosing a CAT takes minutes, take it elsewhere as it will probably be quicker & cheaper in the long run!

dave said:

3 miles killed mine, could see bits of hot cat coming out the back glowing red

Click to expand...

turn the nitrous off next time

this car really needs going to a place that understands cars rather than one where they can nail discs and pads on