Have just bought a Fiat 500 for my wife and it has a very bad misfire.
Is will be going back to the garage but I notice it seems to be a regular problem among owners.
Any clues at to what it may be to look for.
Car starts and runs ok but when accelerating away cold it misfires, the harder the acceleration the worse the misfire.
It is less noticeable when hot or when driven gents, but will still do it at wide throttle openings in higher gears, it is a misfire not a shudder due to being in too high a gear.
I understand plugs and cables have been changed, as problem was reported over a year ago, but not solved.

Hi and welcome.

Which engine do you have? I'm assuming here the 1.2 POP?

The plugs may well have been changed a year ago, but how many miles has it done in the interim? Also, this could be a coil pack problem.

What sort of history has this car got? How old is it?

The car is 2012 and has done 24,500 in total since new.
2 services last one at 24,000
misfire reported at service, Fiat checked out no problem found, owner to monitor.
Car is guaranteed so going back but I would like some idea of possible cause.
Fiat garages seem not highly recommended by most users.

Sorry, it is a 1.2 lounge

Did you buy this car from a Fiat dealership or an independent garage?

I still think this might be a coil pack failing, however I'd also be studying any service sheets you have with the car to see whether or not the spark plugs have actually ever been changed. They're pretty crap after 11k miles, so if they haven't actually been changed, especially if the previous owners have only ever had a low mileage service carried out, then they won't be much cop. Also, make sure the air filter has been changed, again, air filters are often left two or three years without being changed and if it's blocked, the engine will be struggling to breathe.

As for servicing, you might do well to find a good independent Fiat specialist. What part of the country do you live at?

terrythorpe said:

Have just bought a Fiat 500 for my wife and it has a very bad misfire.
Is will be going back to the garage but I notice it seems to be a regular problem among owners.
Any clues at to what it may be to look for.
Car starts and runs ok but when accelerating away cold it misfires, the harder the acceleration the worse the misfire.
It is less noticeable when hot or when driven gents, but will still do it at wide throttle openings in higher gears, it is a misfire not a shudder due to being in too high a gear.
I understand plugs and cables have been changed, as problem was reported over a year ago, but not solved.

Click to expand...

I'd agree with Frupi. The symptoms you describe are identical to those I experienced when a coil pack failed. The problem, in its early stages, was intermittent and didn't show during test drives by my mechanic so I left it with him overnight to start from cold and he finally realised I wasn't imagining it. New coil pack and I never looked back.

terrythorpe said:

Sorry, it is a 1.2 lounge

Click to expand...

Hi,
plugs and leads 1st,
then clear fault codes and drive - any misfires will then be stored, and SHOULD be tied to a specific cylinder to aid diagnosis, :worship:

as said - the coil packs are cheap and easy,

:idea: the car is now out of FIAT warranty.., so you could use ANY garage that knows what they are doing,

the basic engine set-up has been around since the 90's Punto, so every mechanic will have seen a few

Charlie - Oxford

varesecrazy said:

as said - the coil packs are cheap and easy

Click to expand...

Easy, yes - you can change the coil pack in less than 10mins; just take off the air filter box & then undo three bolts.

Cheap, sadly not - unlike previous engines, the Euro5 1.2 FIRE uses a single encapsulated coil pack & you have to replace the whole thing.

The well-documented coil pack problems on the 500 were, IIRC, restricted to the 0.9TA engine.

The original fit plugs on the 1.2 will be worn out after 10,000 miles and as others have said must be the prime suspect. I don't like trying to diagnose problems from a keyboard, but replacing the plugs with something better than OEM is worth doing anyway and I'd say this would have a good chance of providing a permanent cure.

I wouldn't be splashing out £100+ on a coil pack without specific evidence that the existing one is faulty.

Hopefully the OP will have it all covered under their car sales warranty,

I was just explaining the process of diagnosis.

I take it the circa £100 coil pack is a FIAT price,

remembering the old sealed unit from the 16V engines was @£50
but Supposedly £266 list:nutter:

Charlie

terrythorpe said:

Have just bought a Fiat 500 for my wife and it has a very bad misfire.
Is will be going back to the garage but I notice it seems to be a regular problem among owners.
Any clues at to what it may be to look for.
Car starts and runs ok but when accelerating away cold it misfires, the harder the acceleration the worse the misfire.
It is less noticeable when hot or when driven gents, but will still do it at wide throttle openings in higher gears, it is a misfire not a shudder due to being in too high a gear.
I understand plugs and cables have been changed, as problem was reported over a year ago, but not solved.

Click to expand...

Hi Terry,

Various technical answers above which I would agree with to be honest.

My only other take is on the mileage. If I have understood your post correctly, are you basically saying the car was given its second service last year? In other words, has it only done a few hundred miles in the past 12 months?

If so, maybe an Italian "tune up" is the order of the day! Might just be in need of a bit of a blast to blow out the cobwebs.

If not and it was serviced recently, then perhaps both you and your wife could take the car out and one of you film the fault. I note you are planning to go back to the garage, so that would provide some extra evidence.

A brand new coil pack can be had inclusive of postage, around £65, so if the dealership diagnoses a coil pack fault and then wants to charge silly money because they refuse to do it under warranty, then I'd purchase this:

https://www.rexbo.eu/ngk/coil-ignition-48169?c=100150