For my '04 Cayenne, it was the tranny valves. It started when my wife was driving on the highway when she punched it to merge lanes. The car stumbled and then shifted very hard into a lower gear. Then it disappeared and would appear from time to time. No codes whatsoever. Dealer confirmed the tranny valves in the early models were a problem. It was a $2-3K fix as I recall but then again, any trip to the P dealer was always $1-2K ;-)

 

Whew..Here I go again. The code returned. I replaced the Bank 1 MAF, not fixed, switched the MAF to the other side, and all my codes went away and the CTT is running really great....but a few days later, now I have a Air idle valve code. I cleaned the throttle body and butterfly flap, and cleared the code. It returned. Takes about 2-3 days. That code keeps popping up. It's the P2235 and P2237, so I doubt both my pre-cat O2 sensor went out at the same time, even if I was running rich for awhile. I'm stumped again, but really happy with how she is running. I need to fix this for inspection. Thinking it is the purge valve, or the seal at the throttle body may be leaking a bit. Any suggestions this time? Getting closer.

 

Im having a similar issue wiyh my 04 CTT

It seems to cut off out on low throttle to a point when trying to overtake, it pauses for a but and then starts going I got the same "value exceeded" error as well. Dealer checked it and said must have been bad fuel. They couldnt find an issue

Any ideas.

Now after the latest episode dealer wants to change the fuel pumps

 

Found my problems.. MAF sensor went out. I found a vac leak by spraying throttle intake cleaner around all potential leak areas and wait for a stumble with engine running. It stumbled. It was the T-Hose just under the throttle body. looks like it must have rubbed the behind pulley. Fixed the vac leak and now all is normal. All those codes disappeared and no dash lights. I also deleted to second cat. Doubt that helped anything, but sounds a little better.