uneven idling / misfire cylinder 2

[stevevwuk]

Hi all, hope you might be able to help. I got a 2002 BBY 1.4 16v polo off a friend 78k miles. He had some issues with intermittent idle. It drove 100 miles home absolutely fine, then some days later the problem came back. It runs ok when cold but when up to normal temp after about 15mins idling it starts rough.

It was giving the following code: 16686 / p0302 on number 2 cylinder. If you clear the codes they eventually come back.
Am I right in thinking the cylinders are numbered from left to right?

I changed the plugs as I had some and a mate gave me a brand new coilpack to try as a test. Also tried swapping the injector for one from a different cylinder.
One odd thing I noticed was the metal clip holding the injector to the plastic rail on no 3 was missing

None of these fixed it. I got a compression tester and with 10 seconds cranking on each cylinder got the following: 1: 200, 2: 178, 3: 203, 4: 200. I tried a bit of oil down the bore and the compression test gave the same result. The top of the piston in no2 looks dirtier than the others
Could this be valves on no.2?

Any ideas / advice appreciated.

Thanks,
steve

[RUM4MO]

The cylinders are numbered left to right, ie one is next to cambelt, four next to gearbox. With the convenient lower pressure on cylinder two, it does look a bit like valves as some oil did nothing. I've had 106K out of one of them without any internal engine problems.