I’m hoping that some of you trusted 996 wizards might help me to better understand this data from my buddy’s new OBDII reader. The car is a 1999 (9/98 build) C2 (throttle cable car) with an early engine replacement (which has a double row IMS and an 11/99 casting stamp on the crankcase).

I’ve recently done a lot of work to the engine including new head/plenum intake gaskets, new Bosch plugs, new Beru coils, new Bosch evap solenoid, new Bosch MAF, new Bosch “996.2” injectors, and a new Bosch idle air control valve.

The car has a RoW DME flash and thus will only display Bank 1 cam deviations and doesn’t require an operating SAI. Two different deviation values are shown below. The car initially showed 6 when we first started digging into the reader. After a short drive, it went down to 4 and then eventually settled on 5 while at idle after the drive. (Yes, I am aware of FSI and Porsche’s stance on those values).

We were a bit surprised that his reader was able to pull data on the car. All values shown below are with the car running at hot idle. Outside air temp was in the mid to high 80’s.

I’m quite curious if I should consider replacing the O2 sensors? I don’t know how old they but I’ve owned the car for 6.5 years so they are at least older than that. The car doesn’t currently throw any CELs though it does occasionally have a slight burble/unsteadiness at idle, which is most noticeable when the AC is off.