Fiesta 2014 Zetec 1.25 Misfire

[Sert510]

Hi,

Ongoing misfire with flashing engine light on dash (doesnt always misfire or show up), even though garage has changed coil pack and leads, spark plugs, cracked injector, and software updated the car. Pressure and emissions test are all normal across cylinders. However, the car is still misfiring. Now we think its an electrical issue, perhaps the ECU.

Anyone experience anything similar on this car?

If the ECU fix doesnt work then im going to get an automotive electrician take a look at the wires and connectors.

Bought it 3 months ago and just spent quite a bit getting it to baseline, so I really dont want to scrap it.

[LeftLake]

Hello, does the misfire occur at low RPM or high RPM? Presuming you have swapped spark plugs / coil packs / injectors between the cylinders to see if the misfire follows. The old Noid light test can be used as a very basic way of checking the wiring yourself.

I have had misfires caused due to cracks / leaks in intake hoses before so it might be worth doing a smoke test or similar. Usually you'd get random misfires on multiple cylinders but not always.

There are a lot of 'fake' spark plugs / coil packs out there which claim to be genuine but often are not. Might be worth a check as on several occasions I have known people replace a bad spark plug with another bad one!