I have a 2004 cayenne turbo which recently had a ecu tune performed and my vehicle has been throwing the codes P2189/2187 too lean at idle bank1 and 2. I initially was also getting a code for a leak between the MAF and throttle body in which I found a cracked crankcase hose and fixed that. The codes came back and then one time it was associated with the EVAP code. So I went ahead and replaced the EVAP. The code is again coming back. I did notice that my coils are model 104.00 so they are very old and have never been changed. The car recently has also been studdering alot if the boost is increased too much which sounds like coil or spark plug problems now that the ecu tune is streessing the coils. My plan is too replace the coils and plugs with the newest ones but I was hoping someone might have some insight if the P2189/2187 code could also be related to failing coils and plugs causing a lean condition at idle. I also have had CAI on the car for over a year and never had those codes come up until recently. Thanks.

 

Your tune is causing the charge pipe 0-rings to bleed vacuum/boost. Wrap some Teflon under the new 0-ring lands, so the ring surface seals much tighter.