i have a skoda octavia 19.tdi 2006 , from last week i facing a problem that after  changing  the gear  from 3rd to 2nd the car not taking the accileration. the speedometer and the RPM indicator not showing any movement . it is happen for 5 to 10 second only after that everything is all right . there is no problem with the gear change, no other sound.

 

Please help me to find out the root couse of this problem . 

 

I'm no mechanic and would advise you investigate further but I had a problem similar to this with my car losing power occasionally and struggling to accelerate. It turned out the flutes on the turbo were sticking and so the engine management system thought there was a problem and put the car into limp mode. After a while it would be ok again. I thought at first I was going to be looking at a large bill for a new turbo but through the forum pages and you tube I learned that you can clean them with Mr. Muscle oven cleaner if you are up for doing it yourself. 

 

In the end I didn't need to do this as I was advised by a mechanically minded chap and bought myself a bottle of Wynn's Diesel Turbo Cleaner for £9.99 and added it to a full tank of the high grade diesel (Shell V Power or BP Ultimate). I noticed a difference in performance after about 10 miles. I also did the same thing on the next fill up with a bottle of Wynn's Diesel injector cleaner. 

 

Finally I was also advised by this chap that running the car on normal city diesel is ok but it will leave more carbon deposits around the engine than if you run it on the better quality diesel. He recommended I stop using city diesel altogether and run it on the top stuff which I have been doing. It may be my imagination but I seem to be getting better MPG too.

 

Hope this helps.