GLOWING TERMS

▶ A problem concerning a Kia Cee’d traction light is featured in your recent Help! section (CM, Oct 2019, page 81). The initial part of the question relates to a traction light issue. A second issue is highlighted, which is that the ‘car drives well, but occasionally suffers from a hesitation; it feels as if your foot has slipped off the accelerator.’

I had a Hyundai i30 1.6 diesel, registered in 2010, which I believe shares the same engine. I was the second owner. My Hyundai had similar symptoms, in that it occasionally suffered from hesitation for a maximum of 4-5 seconds. This might happen three or four times in a month.

It was annoying. I replaced the fuel filter with a genuine Hyundai filter but it did not solve the problem, so I took it to a garage in the hope that the issue could be pin-pointed. The mechanic outlined to me that as it was an intermittent fault, it could be very difficult to pin down.

It did not have any fault codes stored. The mechanic checked the live data at various engine revs and told me that, as far as all readings were concerned, the car was running perfectly. He suggested that I keep driving it, let the fault develop, and in that way it may be possible to identify the cause of this hesitation.

Some months later, a heater plug became defective. Number 4 heater plug was shot, totally dead. There was also high resistance on heater plug number 3.

On cylinders 1 and 2, Hyundai heater plugs were fitted. Cylinders 3 and 4 were fitted with spurious, aftermarket heater plugs. I decided to renew all four plugs. About a month later, it dawned on me that the car had not suffered hesitation since I had fitted the new set of heater plugs. After a further two months or so, it still had not suffered any hesitation.

I popped back to the garage, and got talking to the mechanic who had tested my car on the diagnostic scanner. He could not say why there was no longer a hesitation issue – but he did say to leave well alone.

I traded in the Hyundai about 20,000 miles later, and not once did the hesitation return – don’t ask me why! Michael Carty