Hello all and thanks in advance for any help.
Three days ago the cayenne was at the dealer for An oil change and utility belt replacement , I just did a bit over 11 KM road trip across Canada .no cel codes found all clear from the service advisor to drive back home ' 5000 km'
problem stated the next day when at high speed when selecting a down shift from 6th to 5th , the car would bog down for a second or two with almost no power but recovers fast , I just filled up with 94 octane fuel but from a very remote area
i had the car for 6 years with no major issues , bought CPO in 2011 " HPFP" was replaced at that time .
now I am at a remote location but found a Porsche specialist mechanic whom suggested fuel filter after finding codes
P1026 and P1027
car starts fine with no issues , pulled fusses 13 and 14 one at a time no problem engine stayed on ,
scanned it with multiple scanners , no cel codes .
just after changeling the fuel filter the car shutters at any throttle position above 50 km.
low pressure fuel pressure at idle is 40 bar. Stopped and key out just about 40 bars .
revving the engine when stopped rpm goes only to 4000 rpm. Fuel pressure goes up to 60-65 bars.
but when driven with the scan tool plugged in , actual fuel pressure drops to 20 bars .
car was running at its best with just the bogging down at high speeds intermittently , now with a new fuel filters it's barely making 50km/h above that it will shutter and looks like lots of moss firing , no cel codes stored nor active
any ideas please