Hi,

I have a 2001 1.4 16V Skoda which has only done 27,500 miles. I have had the car for almost two years now and purchased it with a 1-year warranty. From Horners Skoda (which has recently closed).

Over the last couple of months I have noticed that the revs will fluctuate intermittantly whilst idling instead of the revs being at around 900RPM they will fluctuate between 500 - 1400 RPM, after a short period of time the revs will return to normal.

I have also been driving down the motorway at 70 MPH when the rev's suddenly dropped making the car judder, before the revs increased again.

The car has been taken into the garage for investigation on several occasions I have had a replacement EGR valve installed, and a full service undertaken. But the problem still persists.

Does anyone have any ideas what could be causing the problem?

Best Regards,

PAO72

What are the fault codes?, why did you have a replacement EGR valve?, was it showing an excessive flow rate?

I would guess at a blocked EGR pipe at the inlet manifold end and a very dirty throttle body.

Check for faulty coolant temp sensor, this may result in floating revs

Thanks for the replies so far.

When I orginally identifed the symptoms I took my car back to Horners Skoda for the annual service and advised them of the symptoms I was experiancing.

I expected the car to be returned to me the same day, but was told that they would need to order a part and they kept my car in for another day. when I arrived to pick up my car I was advised that the throttle sensor was faulty, there was a leak on the radiator and that the rear brake drums needed to be replaced along with a general service (all this on a car that had only done around 17,000 miles) I was not amused when they advised me I had to pay 700.00 GBP! :eek:

I paid the bill and left rather enraged and promised myself not to take it back! A few weeks later, the fault symptoms re-occured. I found a local independant garage who had the equipment to check the engine management system for error codes and was advised by them that the error code indicated a problem with the EGR valve, they said the cheapest option would be to remove the valve clean it and re-fit it which is what they did. The car drove well for about two weeks before the symptoms re-appeared. I returned it to the garage, they ordered an new EGR valve and fitted it for 150.00 GBP inc parts and labour.

The car dove fine for about a month, then the symptoms came back, I returned it to the independant garage, they connected their equipment again and said that they can't understand why the error code is indicating a faulty EGR valve as a new one had been fitted. The garage reset the error codes and advised me to take it back to Skoda if the fault re-occurs as they might need to re-configure the engine management system rather than just resetting it (e.g. have it reset to factory default settings). I was going to do this but Horners Skoda have since gone into liquidation .

On top of the EGR valve there is a variable resistor, the position of the resistor tells the ECU how far open the EGR valve is. If the EGR valve is open, exhaust gasses will be directed into the inlet manifold under the throttle body. As the ECU is expecting a certain amount of exhaust gasses it will alter the fuelling to compensate. As the pipe under the throttle body is restricted the exhaust gasses are not getting through, so the ECU requests the EGR valve to open a bit more, this continues until the the EGR valve is fully open - hence the excessive flow code.

If a garage is not aware that this pipe gets blocked the first thing that they will do is fit a new EGR valve. What is required is to remove the throttle body, disconnect the EGR pipe at the EGR valve and clean the pipe and blow it through with compressed air, from the inlet manifold side. Whilst the throttle body is off, it can be cleaned as well.

Armed with this information your independant garage should be able to sort it for a cost of around an hours labour and no parts.