My problems continue... Check Engine Light:

Great, so no sooner do I resolve the CAT issue does something else come up. :wall: Helf way home and the check engine light has come poped up on the dash. Great. Now waiting to get hold of an OBD2 port reader so I can see what the error code actually is. Right now, my bet is on the Lambda sensor that was loose, or the coil packs. Cayman S, 2006. God I hope this is not a sign of things to come. I looked on design-911 but cant seem to find the right OEM coils (just trying to get an idea of costs). Really am hoping its nothing more serious than this.

I'd be ever so grateful if someone were able to point me in the direction of any other online shops apart from design-911 that might be good places to source components such as coil packs in he UK.

I think scuderia car parts sell Porsche parts in UK, I've interacted with them once over another part.

Is the engine missfiring or running rough? If not then its unlikely to be a coil pack. A couple of places here worth compairing prices from: Euro Car Parts | The UK's Number 1 Provider of Car Parts Online and In Store [url]http://www.porscheshop.co.uk/index.html [/URL]

Down low, it seems to dip a bit and miss. Might just be me. I checked the filler cap. It pulls fine.

That could be a faulty MAF sensor. Let us know how you get on.

Will do. Should have a wireless obd2 reader by the weekend so will update. Cool pack don't look ridiculously expensive.

Right, one code showing: P0431 warm up catalyst efficiency below threshold bank 2.

Looking around on here briefly, it looks that the two most obvious issues will either be the O2 sensor downstream from the CAT or the CAT itself. Initially when I bought the car, I was under the impression that I had heat shield rattles. Upon taking it to a garage, they looked at the car sorted the heat shields and told me the main rattle was from one of the Manifold CATs. The guy popped it up on the ramps for me and I tapped the 'faulty' CAT and indeed it was rattling. Last weekend, I subsequently took the car to another garage for them to look at because it still sounded like it was blowing as well. This yielded good news. The guy looked around it and discovered one of the Lambda sensors was loose on the CAT in question. This was the cause of the rattle on that CAT and was also the source of the blow. He tightened it back up and, job done, the rattle and blow was fixed. I went away a very happy boy indeed! If anything the car is running better than before... Yesterday, on the way home from work, the CEL light comes on and throws the above error. So now I am wondering what it is more likely to be. Could the chap who owned the car before me have backed off the Lambda sensor in order to stop the CEL from being thrown and passed it off as a heat shield? Would the fact that it's been loose likely damaged the sensor or is it the CAT?

Yes that's a common thing people do, either back it off or put washers between the sensor and the cat to pull it out of the airstream more. The real issue is that in early 2006 model cars Porsche's ECU programming had tighter (smaller) ranges of accepted values plus the cell structure of the cats was more open (less dense) (I think it was 400 cel cats). Lots of early cars tripped their check engine lights because the ECU didn't like the values it saw. Porsche released 2 fixes. 1) An ECU update in 2006 that if your ECU gets this (or newer) ECU flash it will tolerate a wider range of values 2) Porsche replaced under warranty the cats with a higher/denser cell cat (500 or 600 I can't remember) Usually 1 or 2 or both in tandem cured any touchy and essentially false check engine lights.

Like many on here with similar issues, I'm a bit wary of knocking back the sensitivity of the ECU. The potential risks worry me quite a bit. If the CATs falling apart I want to know about it. I've reset the light and will see if it pops back on. Before the light came on, I had sat at idle for around ten minutes.

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That doesn't make any sense, it isn't like a failed cat isn't going to trip the check engine light with the updated ECU parameters. As I said some people even with the ECU update still got the check engine light until they replaced the lower cell cats with higher cell cats and that ended up curing the problem, so the ECU is still plenty sensitive enough to spot failed cats, it just isn't overly sensitive to trip a light on a start up that is slightly out of spec.

Okay so, the lights not come back on since switching it off. Could it be that the ECU tripped out because there was a sudden increase in readings after the sensors been screwed back into the exhaust properly?

Usually it will take an entire tank's worth of fuel to return. Once the low fuel light comes on it should trigger the CEL, if it's pending at the moment. Sent from my iPhone using Tapatalk

Sure but at some point your CE light is likely to return if your sensors are sending readings that are right on the edge of acceptability. Long term fixes include: 1)Aftermarket ECU Flashes 2) Updated Porsche ECU Flashes 3) Updated primary header/cats from Porsche Maybe you can put washers in to space your sensor more out of the exhaust stream and not trip a light for the rest of the time you own the car, or maybe it will trip again after another tank of gas, or next week, who knows. The crux of the matter is that it isn't a serious issue, more one of annoyance, but there are long terms fixes available should you decide to choose one.