Fault codes

Hi all. Car has been laid up for the past 12 months but have decided that it needs to be my daily drive again. Started it up and whilst it starts OK as soon as I put my foot on the pedal it loses power. Ticks over ok but can't get enough power to pull away without it stalling. Put a diagnostic check on it and the following came up. P1602 factory fault code 108-power supply open circuit P0300 factory fault code 75 misfire damaging to catalytic converter P0302 factory fault code 64 misfire, cylinder 2, damaging to catalytic converter P0304 factory fault code 66 misfire cylinder 4, damaging to catalytic converter P1319 factory fault code 62 misfire emission related P1314 factory fault code 51 misfire cylinder 2 emission related P1316 factory fault code 53 misfire cylinder 4 emission related Am I right in assuming that all these are related to a possible coil fault on banks 2 and 4? i serviced the car just before I laid it up 12 months ago changing air filter, oil filter, oil change etc but have yet to change overdue plugs. Before I look at the plugs and coils do any of the codes above lead to the petrol filter or should I just go ahead and do the coils and plugs? thanks in advance for any advise.

Hi David That's bad news, I'm sure Richard will come along later and give you his advice. Where has the car been stored for the past year?. My first thoughts would be fuel related, poor fuel pressure, muck, faulty pump, Injecters?. If the car has not been kept nice and dry then coil packs could all be shot. Best of luck and hope it's up and running soon. Kind regards Andy

As well as coil packs I would be thinking of the fuel itself. It doesn't have a shelf life of one year and was the tank full or partially full? If partially there could a considerable amount of water in there.

I would start with coil packs and plugs if it was me - certainly check them visually. The P1602 code is most likely because the battery had been disconnected or gone flat. The others are all misfire codes. They could be due to sticky injectors perhaps - may be gummed up due to the time left standing, so some injector cleaner in the fuel tank might sort that out.

Cheers Richard, car has been kept in garage with about a third of a tank of petrol. Will jack up the back and try to access plugs and coils. Will also put some redex in the tank. However, is there an easy way to drain the tank of petrol and put fresh petrol in?

No easy way to drain it I know about. I had a similar issue with my 3.2 last spring. It started on about 3 cylinders. I put in some injector cleaner, and it cleared after a while. I blame the ethanol in the fuel, which can cause gumming on older injection systems. I now use Ethomix with the fuel, and no further problems.

Not specifically not help with this scenario, but, related. I picked up the 996 The Essential Companion earlier in the year and there was a section on Winter Storage and filling the tank, to stop water condensating inside a half empty tank from what I remember. So, as has stated above, water in the fuel could be an issue. Worth a read or look at if anyone else is thinking of storing over winter months. There were some other helpful tips too, but I hope not to be actually storing it, maybe just using it less Hope you get it sorted

Omg, can’t believe it. I think my diagnostic check was an old one that I sorted some time ago by replacing coils 2 and 4. Anyway, car as I said starts ok but when accelerator is pressed the car struggles and cuts out. I’ve now replaced the spark plugs as they were well overdue. All coils were in excellent condition as far as I could see so everything fitted back together. allowed car to tick over for a bit and after a while started to ease the accelerator which seemed to work a little better. Think tomorrow some injector cleaner as Richard said and see how things go. By the way, coil pack heat shields just crumbled away, literally very little left

Looks all sorted now, hopefully. Had a senior moment earlier so additive put in fuel tank, left the engine running for a while then revved heavily a few times. Seems to be running much better. Must have been a fuel issue. Anyway, placed the diagnostic checker on and deleted all previous faults. Ran the check again and car is completely fault free, including the engine check light being switched off. Next thing to do is get new coil heat shields.

eek

Been on the car for 20 years having covered 122k so only expected really. Heat shields are slightly cheaper buying at Porsche than buying from the internet, just in case anyone is interested

On that subject sorry to butt in, but do the new heatshields fit the 3.4? Or do they still have stock of the old part?

I would suspect the fuel being the culprit. I would give it a service, oil, filters (inc fuel), then run it with Shell V-power on full tank. Give the car a good run on a long drive. Get all sort of issues if the car if left unused.

I gave them the part number 996-104-425-02, collected and both fitted fine. If that’s any good

Thanks, wasn't sure if OPC still had them stocked as they foul the coil packs on the new design of coils. On the new coils they touch the coil unless you put spacers (awkward) like any 911 job. Thus transfering the heat to the pack ( not ideal) I've also heard that the newer heat shields fit the 3.4 giving more room for the taller coil pack, but have heard just as many people say they don't Argh, the human race.