with my van, i would be driving round the m25 say at 70mph then i would have to slow down for whatever reason but as soonas i put my foot back down the accelorator i had nothing, i would say break from 70mph to say 50 then as i say, foot down and would just about creep up then gradually start lose all power but very slowly , even with the foot flat to the floor, van was still running but revs would not raise at all. So pulled over stopped van, idling perfect but when i pressed the accelerator not much at all, would slowly creep up to say 3000rpm but a real struggle... managed to get her back to my mechanic and he changed the maf for another one ( this is the 2nd pattern one now) and i drove off fine.... 2 weeks later same thing again, it was sort of like doing 0 to 50 in 15 minutes, Back at mechanics, this time it stayed there he checked everything, everthing fine, checked Maf sensor, it had gone again...so this time he got one from the main dealer (twice the price) fitted it to the van, never had a problem since but yes i had not idling problems with mine but mine was power issues as i say i would have foot flat to the floor and the revs would hardly raise, started out very similar to what your car is doing then over the coming weeks got worse.....but was all down to Maf sensor and my van does nt like pattern parts but my mechanic was saying it is really common on most cars especially with maf sensors that the pattern parts are not so good ( maf sensors) and only seem to perform on original parts....