What could cause that rarely (every 1 of 20 starts) car has more power (especially at 1000-4000rpm). It is quite noticeable difference. This happens mostly when weather is cold (below zero degrees) but not always. And this "power mode" last only 10-20mins. After engine is hot power is back to normal state. Lambda sensor could be one that comes in after engine is warm but how it could effect so much? What else could cause this?

 

During cold start, engine is programmed to run rich and ignition timing is optimised to suit hence te extra power felt.

I get the same feeling on all my cars, once hot engine it goes back to normal.

 

Sounds logical but it happens only sometimes. What I have read I think it might be faulty DISA. Have to check it soon.