was the coil pack a genuine one ? these are really common on the 1.8's ! what make are the plugs ?

Few years ago I had a few of these 1.8's suffereing misfire and it was caused by either faulty oil pumps or incorrect oil in the engine causing the hydraulic tappets to over-jack ! Some pumps were faulty with sticking pressure relief valves ! known issue !

Thanks for this thought.

The coil pack is genuine and came off a known working car with 46K on her. Thing is when I took it off, I used its ht leads as well and the problem was identical. I changed the two external ones for new because I thought if there was to be a problem with the leads it would be on these two. I will now order two more just to confirm this.

Regarding the oil. When I bought the car, two months ago, I changed all oil, filters etc to see if this was the problem. I used semi synthetic oil which I think was castrol but I could be wrong. I had heard that sme oil filters can cause similar problems but changing his for an OEM filter had no effect.

This pressure relief valve you mentioned, does that require an oil pump change. I am highly suspect with this because I have heard rattles from the tappits when idling.

Appreciate your help.

Paul

Any difference when damp?

At tickover (& safely parked!) try flooring the throttle briefly - does it suddenly misfire and sound like a 2cv?

Gut feel (difficult to judge from the other end of a web browser) is a HT ignition issue. Why did you only change two ignition leads? I thought at this age this engine had individual coils on spark plugs - or is this just the 1.8 turbo however presuming you have a coilpack and leads you have a wasted spark ignition system in which case why did you only change two leads? Within the coil pack there are two coils each one driving two cylinders firing on one but "wasted" on the other. A faulty lead will affect two cylinders. I would recommend changing all the leads.

The other possibility is a faulty coil pack despite its replacement. There are many slightly dodgy pattern parts, was your replacement a VW OEM part?

Hi and thanks for your help!

There does not appear to be any difference when damp, in fact there seems to be little pattern in it at all. On a couple of occassons, she drives like new. Then she will drive like a marakesh taxi (camel). On the odd occassion I have turned her off, straight back on again and she worked perfectly.

As I mentioned in the above reply, I bought a coil pack from a known good runner, with the ht leads. I changed two external ones for new but will order the two internal ones. Either way, chaging them for known working ones suggests the problem is elsewhere. This coil pack supplies all four pots and is enormously expensive £200+ from europarts so it must just be the turbo that has the individual pots.

Appreciate your time

Paul

Many thanks again for your time. I am sure the oil was the correct oil for the car, that said I did hear noisy tappets post oil change when the car had been idling for ten minutes or so. A quick blip on the accelerator stopped this though.

I will have a good look at the breaher pipe this weekend if I get a moment. In cumbria, finding a garage with a mechanic in it is a bonus, never mind tools as well, less they are for a tractor.