Thank you for that pointer, I did fill up with fuel and after 4-5 miles went back to not going above 2000rpm. next morning I tried what you suggested no vacuum noise but engine ran as normal. but the strange thing is it has not occurred since fingers crossed.
evening all,my first post. As title my freelander will not go above 2000rpm after i fill up diesel tank, untill I do 150-200 miles then it will go as normal.