Hello. My friend has a 2009 Fiat 500 Pop 1.2L 8v.

It was misfiring due to a bad coil pack. She had that replaced at a garage. She isn’t totally sure if she has the plugs swapped at the same time.

However, since then the car has developed a very rough idle. It doesn’t stall but it judders heavily.

I noticed a breather pipe attached to the air box from the inlet manifold was damaged. I replaced it. Didn’t fix it.

I’ve swapped the HT leads. Same issue.

I haven’t bought new plugs yet as she says they was done at the same time as the coil pack so I’m working on the assumption that they are new.

I’ve checked the air filter and cleaned the throttle body.

There is no engine management light on.

I’m running out of ideas guys. Any suggestions?

How does it run the rest of the time?

Maybemaybenot said:

How does it run the rest of the time?

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Quite normally. It seems to be fine when it has a few revs.

Old school but I'd start with an Italian tune up.

Maybemaybenot said:

Old school but I'd start with an Italian tune up.

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Just floor it?

Exactly. Get her good and warm then thrash her for a few miles. Can work wonders. Lots of revs.

Take out a plug that'll tell you if they're new? If not new replace with Iridium not standard.

Updating this thread in case anyone finds if with Google.

It was a crankshaft sensor that was the issue.

Replacing it has solved the problems.

A symptom that occurred later down the road that pointed to this was the rev counter stopped working too although the issues were presenting for quite some time before this happened and the other symptoms became progressively worse.