Bright sparks

As an AA garage, a car was delivered that had developed a "judder" with poor acceleration after driving from Tamworth in Staffordshire on the way to Devon. The AA patrolman thought the catalytic convertor may be blocked, but he had no relevant faults on his diagnostic computer.

Strangely there were no relevant faults in the ECU. If there had been a catalytic convertor issue then there should have been faults, which was very strange. The engine sounded very "lumpy", but there was no obvious misfire.

WMM suggested that we KISS (keep it simple stupid). Start with the cheap stuff before we start looking for complicated things.

The customer had only owned the Ford Focus for just over a year, and prior to the holiday it had been serviced at a local garage.

Straight away, WMM encountered a problem. Number two spark plug was extremely tight. WMM inserted an expensive spray into where the spark plug was housed and left it for a few hours.

If the spark plug had snapped, this would then mean that the cylinder head would have had to be removed, a very time consuming and costly repair.

The spark plugs clearly had been in a very long time, but we managed to extract the spark plug with only minor thread damage.

With the old spark plugs out and the new ones side by side there was an obvious difference. The old spark plugs were completely unsuitable for this vehicle.

Someone had fitted four short spark plugs. These were incorrect, but to be fair had done well for the time they had been in. Once the correct plugs were fitted, the car ran as it should and the "judder" disappeared.

If you have a concern about your vehicle, call us on 01905 358217 or email wmmgarage@gmail.com