DannyHoffman

I only trickle charge it after it starts playing up, or if I am making a longer journey when it would be inconvenient if it broke down. I have done short journeys without trickle charging it for over a week and had no problems. Two things appear certain 1) It always plays up within 5 miles of filling up, whether motorway miles or around town 2) Trickle charging it overnight cures it till the next fill up I might try only half filling the tank next time

Well yesterday I had to fill up half way through a 60 mile motorway run. True to form a few miles after the fill up it started to stutter. I pulled over and fitted the brake hose clamp to the flexible hose at the front of the purge valve, but it was still the same. I loosened the tank filler cap and it was still the same. I got within half a mile of my home before it became difficult to drive. The fault code reader showed: P0441 EVAP Emission control Sys incorrect flow which I assume is because I had blocked the purge valve pipe or removed the fuel cap. I cleared the error. Battery voltage with the car off and locked was 12.79v measured under the bonnet. I put the trickle charger on overnight just in case. It drove perfectly this morning

I had a quick look at testing the purge valve as suggested, but am a bit nervous I might break it removing the hoses. And as I don't have a spare I could render the car undriveable. If I were to clamp the flexible hose at the front of the engine with a brake hose clamp next time it starts to stutter would this eliminate the purge valve? I have also ordered a volt meter that plugs into cigarette lighter (which has yet to arrive) so I can monitor the voltage in real time next time it stutters I expect to be filling the tank in the next day or so, so watch this space!

I have tested the new battery under load and after the car has been sitting overnight and it appears to be fine - 12.9v with the engine off and everything else turned off. I am getting 14.2v at idle so the charging system seems to be healthy too. Is there a way to test the purge valve for leaks or is it just a case of replacing it ?

I had to do an early airport run this morning and didn't want to risk any problems so stuck the trickle charger on last night as a precaution. It ran faultlessly all day to day. Thanks all for the suggestions. Re the evap purge valve, would loosening the fuel filler cap eliminate this if it starts to stutter again? Re fuel pump/pressure - I would have thought this would be more likely to be the cause at higher revs, when it plays up it is worst between 1,600 and 2,000 revs at light throttle

"The current coil packs are: 948 602 104 21. You are about 3 revs behind. " I changed them all even though the old ones didn't have any cracks

The sticker inside the filler flap says 95/98, the handbook says the engine is optimised to run on 98. Shell V-Power is 99, so it's an interesting suggestion

I filled up both times with Shell V Power at different petrol stations

My very recently acquired 2006 Turbo S 73,000 miles started misfire yesterday shortly after filling the tank with petrol. The more I drove the worse it got until the point where it cut out completely and the engine check light came on. I restarted and limped home I have a Maxidiag EU 702 fault reader which supports a number of car manufacturers but not Porsche. However the generic OBDII mode and the VW specific mode read the following errors: P0492 Secondary Air Injection System Insufficient Flow Bank 2 P2177 System Too Lean Off Idle Bank 1 P2179 System Too Lean Off Idle Bank 2 P0300 Random Multiple Cylinder Misfire Detected P0301 Cylinder 1 Misfire Detected P0302 Cylinder 2 Misfire Detected P0306 Cylinder 6 Misfire Detected P0305 Cylinder 5 Misfire Detected It felt like coil packs and was due a new set of plugs so I changed them all today. Whilst doing so I noticed that the hose to the secondary air pump on bank 2 was completely disconnected, possibly explaining the first 3 errors I couldn't see any cracks on the coil packs and their part number ended in 07 which from what I have researched means they were manufactured in 2009 ish, around the time of the last plug change The plugs were all a similar very dark colour. I cleared the errors and the check engine light now stays off. Is there anything that could cause a misfire on all 4 of the front cylinders only? I have visually inspected all the vacuum hoses. Drove it again and it definitely still isn't 100% right. I got an occasional minor stutter both cold and hot. Fault reader now only had the following: P2177 System Too Lean Off Idle Bank 1 P2179 System Too Lean Off Idle Bank 2 I cleared them and it still misfired, but I only drove a short way and the codes didn't return. I looked back through the limited service history I have for the car and in April this year the car was taken for a diagnostic test. The hand written report has the following: 1) Secondary Air System Bank 2 Below Limit Value 2) Vehicle Electrical System Voltage Via Main Relay. No Signal It doesn't give the P numbers. I'm assuming the first error was due to the secondary air pump hose being disconnected, could this have been off since the last plug change in 2010? The second error is a little less clear from a quick look on the forums. One post suggests it is to do with parking assist, another to do with a faulty relay for the fuel pumps and another for a low battery voltage. After reading the forums I found a few suggestions that low battery voltage could cause strange misfire issues so I attached a trickle charger overnight which showed the battery charge was less than 80% charged. My car has done very few miles in the last year and since I've had it I've been doing various bits and pieces which would drain the battery (tailgate shocks, tracing a Bose amp fault) and only done short journeys. I also read about the PCV/Oil air separation membrane and have checked mine. It has a 1/4 inch split and a smaller pin hole. I have temporarily put a dab of glue and some tape on these. A new one is on order. The engine now has a lovely creamy feel to it 99% of the time, smoother than any of the other Cayennes I test drove whilst looking. There were no fault codes logged but I'm am still getting a very occasional stutter. After getting the battery 100% charged I then tested the battery and it was indeed failing, so I fitted a new one. The new membrane arrived so I fitted that. All was well for a week until I filled up, and then about 5 miles later it started to stutter occasionally about 3 times over a 5 mile journey. The battery voltage is good (12.9v when the car is turned off and locked). No faults have been logged Could having a full tank of fuel cause a problem? Any other ideas?