Engine misfire repairs

The consumer’s issue:

“I purchased a brand-new hatchback in 2013. Five years later, at around 80,000 miles, I had the cambelt replaced by an independent garage. However, following the repair, the car developed an incurable misfire. The business has carried out several investigations, but they haven’t been able to locate the fault.

I therefore took the vehicle to a specialist, and they also weren’t able to find the underlying cause of the issue. They suspected the problem was due to an inherent defect with the ECU software, and they advised me to return the car to a manufacturer-approved dealership as they believed the engine might need replacing.

I also had the car inspected by an independent ACE engineer and they found that the independent garage had carried out all repairs correctly. Therefore, the issue must be a result of an inherent manufacturing defect. I subsequently found out that, I not only needed a new engine, but also a new twin-clutch system for the gearbox. I took my vehicle to an approved dealership for the repairs to be completed, but I am looking for the seller to provide some financial compensation because I believe they sold me a faulty car. In fact, I was without my vehicle for six months, and it has cost me £7,500 to get it back on the road.”

The accredited business’ response:

  • The customer contacted us about an issue with the car misfiring after repairs had been completed by an approved dealership.
  • The electronic fault code recordings on the car’s onboard system were indicative with the timing initially being set incorrectly during the cambelt replacement.
  • The customer had confirmed that the misfire only developed once the cambelt had been replaced.
  • There’s no evidence indicating that the car was suffering from a manufacturing fault. Therefore, we won’t be providing any financial compensation to the customer in this instance.

The adjudication outcome:

  • The Motor Ombudsman adjudicator remarked that the consumer had been able to use the car for over five years and covered considerable mileage in it.
  • The adjudicator said the fault had developed only after an independent garage had carried out repairs, so it was more likely than not that it was this work that had triggered the problem.
  • Therefore, there was no evidence to suggest that the car had been faulty at the point of sale, or that it was indeed suffering from a manufacturing defect.
  • Based on these findings, the adjudicator could not uphold the complaint in the consumer’s favour.
  • The customer was unhappy with this outcome and requested a final decision from the ombudsman.

The ombudsman’s final decision:

  • The ombudsman reviewed the information and agreed with the decision reached by the adjudicator.
  • She said the consumer hadn’t complained about any major issues with the car until it developed a misfire some five years and 80,000 miles after they had bought it.
  • The ombudsman considered the independent reports provided, but she didn’t think they were proof that the car was suffering from a manufacturing defect.
  • The ombudsman explained that the car had been taken to an independent specialist that hadn’t been able to determine whether the misfire was a result of a previous cylinder head repair or whether it was software related.
  • She also noted that an ACE engineer hadn’t been able to determine what the cause of the misfire was and had recommended further dismantling and investigation, but this hadn’t been done.
  • The ombudsman said the consumer had covered above average mileage with the car during five years of ownership, so considered the engine to have been sufficiently robust and durable.
  • They also remarked that the customer had confirmed that the misfire had only started following a cambelt repair, so this was proof that the car hadn’t been defective at the time of sale.
  • The ombudsman concluded that there was no evidence to show that the cause of the fault existed at the time the consumer took delivery of the car, meaning they could not uphold the complaint.


  • The consumer accepted the ombudsman’s final decision, and the case was closed.