No offence ment to you fago but cars have ,moved on in 23 years, just because you have been driving for so long doesn't mean you have been driving right.
In general people who drive petrol's and diesel's are unable to swap, it takes time to learn to drive a different car and get use to the style it requires. We rent cars to people when in for service and sometimes we end up giving out a diesel to a petrol car owner and other way round and 9 times out of 10 they come back saying there is something wrong with the car and we should get it check out.
Petrol owners tell you the car cuts out, diesel owners say it revs very high etc. It takes a bit of time.
If your that worried about it go to the garage and ask to drive a similar car and see if there is a lot of difference, it might put your mind at ease.
At the and of the day it is a big car with a small enough engine, so it does have to work harder to get the job done.