If you ever come across a problem with the above mentioned vehicle with the following symptoms
1. Engine sound rough
2. Performance is weak
3. Engine smoking
4. No faults stored in ECU
After testing sensors
1.No faults on sensors
2. Engine compression is OK
3. Cambelt is fitted correctly
Well check for camshaft and hydraulic lifters wear. I had a Polo with these faults and after replacing the cam and lifters, it fly like a Boeing, I had to remove the cat and fit a piece of exhaust pipe in its place. The cat was almost blocked completely