i recently replaced a fuel pipe on my car and now it likes to sit around 1500rpm but does drop down but is still on the 1000rpm mark

i have cleaned the MAF and also cleaned the ISCV out and reset the ECU
does it take a few miles for the ECU to re-learn as i have done around 16 or so since i cleaned these parts.
could it be an air leak somewhere but how do you test this if all the pipes are tight and there is no sign of damage

any help mucho appreciated