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Help! Check engine light on, rough idle, light flash on acceleration

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08 Cayenne, 70k. Did a 300 miles trip today, on the way back was on cruise control at 75mph. It shifted from 6th gear to 5th gear during an uphill, then CEL flashes and felt power loss. I soon pulled to the side and shut off the engine. (Last time similar issue happened was at 50k and changed all 6 plugs and coils.) Waited 5 minutes and restart the engine, CEL still there. Waited another 15 minutes, still there.


Wife was on panic mode, and since it was a steady light I decide to slowly drive home. During the 60 miles drive, the CEL stays on but flashes only when accelerate on uphill. I have to use Tiptronic and keep the rpm around 2500-3000 then it feel smoother otherwise it shakes.


When finally got home did a Short test on Durametric, the results are below:

Bosch Digital Motor Electronic 9

P0768: Random/multiple cylinder misfire detected – Upper limit value exceeded, test conditions are not-complete, fault is currently active and causing a DTC light.

P0774: Cylinder 6 misfire detected

P0770: Cylinder 2 misfire detected

P0771: Cylinder 3 misfire detected

P0773: Cylinder 5 misfire detected

P0769: Cylinder 1 misfire detected


532: Power supply – value below lower limit value

Air condition

Drive motor for temperature valve left


3C90: Control module for seat occupancy detection

Steering wheel electronic

1749: Tiptronic switch on steering wheel down. Open circuit/short to B+


Cylinder 1,2,3,5,6 misfired, does this mean I only got a cylinder running during that 60 miles drive back home? Can someone help to tell me what I need to do to get the above code fixed? Thanks in advance.

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11 hours ago, wizard said:

It might be an idea to put the vehicle on level ground, clear the codes that you have, start it and see what codes are coming back.


Just did, all codes are back. The car started really bad and sometime it wouldn’t even start.

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When a fuel pump died on my non Porsche vehicle I did the following to diagnose the issue:


1) Used "engine starter" spray (removed air filter and sprayed into intake) to check if vehicle starts. It did.

2) Checked fuel pressure under the hood. There was no pressure.

3) Checked fuel pressure at the pump (had to remove seats and carpet to get there + I had to supply 12V to the pump in order to see how it works. There was no pressure though pump buzzed a bit when it was engaged.


So I assumed pump didn't have pressure. Eventually I purchased a new fuel pump and problem was solved.


Also I'd suggest to watch few random YT videos regarding diagnosing and troubleshooting dead fuel pump.


Though it may be not fuel pump...

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