I have a 2010 1.6 diesel fabia. Last Autumn I got the water thermostat changed as the heater was not very effective and the engine was taking a long time to warm up. The job was done by a competent non Skoda garage. The car drove OK initially but after 5 miles it started to complain. It coughed, spluttered, blew clouds of smoke and stalled. After 10 miles, it improved slowly. I concluded that the CPU was resetting itself to cope with the new engine settings (i.e. a warmer engine).

 

I just cleaned and re-installed the K&N air filter which has been in the car for about 2 years. Again the car is a horror to drive (same symptoms). Prior to cleaning the filter it was running OK and nothing else has been changed. Everything is reconnected and refitted.

 

Any suggestions on how to overcome the CPU having a nervous breakdown every time something on the engine is changed would be appreciated.

 

I should also mention that a few years ago, I bought some Shell diesel fuel instead of buying it from my local Esso garage. Withing a couple of miles the indicated fuel consumption went from 50 to 38. Again it took about 100 miles til the consumption figure returned to anything like the old figure.

 

Why are these engines so sensitive to small changes? Or is it just my car?

 

Did you use the Official K&N Cleaning Kit?

 

I would chuck that in the bin and fit a Clean New Filter that lets the engine breath and fingers crossed no sensor has been damaged.

Doesn't sound like an ECU fault to me. You might want to get your EGR valve checked then check your lambda probes. Have you had a diagnostics check recently? Is the engine light on?

Thanks for your advice. I will get a standard filter and see if that helps. There was nothing obviously wrong before I cleaned the K&N filter so don't think there can be another problem with the EGR valve or the lambda probes. There are no warning lights.

I fitted a standard air filter and went for a drive. Initially the car was horrible. Very lumpy with lots of smoke. After 4 miles the smoke cleared and it became better to drive. After 10 miles, I pulled into a car park. The engine was again very lumpy at low speed and stalled. However, it restarted easily and I continued. I went about 5 miles on a fast dual road which was OK. The last 10 miles was on a country road so at lower speed. Above 50 mph the car was OK. At 40 it was still a bit rough in 4th gear. Then I drove through the local town and the engine hesitated when pulling away. The fuel consumption over 30 miles was only 30 mpg but seems to be slowly improving.

 

So the K&N filter is going in the bin. I did clean it with K&N cleaner, dried it overnight and then oiled it using the K&N product. Perhaps I have put too much oil but the result is unacceptable. A £12 filter isn't a show stopper once a year so that will be the route for me now on.