Well I've tried a lot of things - full services, cleaning the throttle body, new coil pack, ya de da. All these things made incremental improvements, especially the coil pack, noticeably smoother running. But the idle was still Ill mannered at times, with popping and missing.

But I can cautiously report a solution - a speculative can of "Cataclean" fuel treatment. Now I've tried other treatments previously, and I've done long journeys on full tanks of super unleaded, all to no avail. But this stuff seems finally to have got somewhere. Within about 15 min I could feel a difference, and it's remained fairly steady and consistent for over a week now, with the engine sounding even smoother than before.

So I'm going to add another bottle next week - clearly it's dissolved something, and given the previous neglect, another dose can't do any harm.

It's one of only 2 products that I've ever tried that actually made a noticeable improvement - the other being Millars Sport 4 diesel treatment that made a Mondeo tdci run properly.

So for all you 1.8 owners, I recommend Cataclean - it's certainly made a difference in my car.