Help Diagnosing Slew of CEL Codes

[-tWv-]

Hello all,



New member here. I just purchased a '98 986 last week from my BIL who has been daily driving it for the past few years. Recently the CEL light came on and the car has been running poorly (most noticeable is very poor acceleration in low gear). He took it to his local Porsche dealer and they essentially diagnosed the issue as bad catalytic converters and quoted a $6k+ repair bill. He didn't have the money or patience to deal with the car anymore and I told him I'd be willing to do the work, so he sold it over to me.



Looking for some help interpreting these CEL codes and making sure that addressing the catalytic converters is the best first step.



There are 6 total codes reading out (I have an iCarSoft PORV1.0, looks like these are interpreted via their software):



1) 22 - Sensor ageing ahead of catalyst converter, cylinder (4-6)

2) 23 - Sensor ageing behind catalyst converter, cylinder (4-6)

3) 322 - Toothed belt out of position, Bank 1

4) 62 - Misfire emissions - relevant

5) 50 - Cylinder 1 misfire emissions - relevant

6) 52 - Cylinder 3 misfire emissions - relevant



Am I correct in thinking that Codes 1,2,4,5,6 could all be caused by a bad cats blocking up the exhaust flow causing poor O2 readings and misfires? The O2 sensors were recently replaced, so I'm thinking that the readings are correct.



The one that has me a bit worried is code 3 for the toothed belt out of position. Could this be caused by bad cats or is the timing chain truly the root cause?



My current plan is to replace the stock headers/cat with the Manzo headers and see if that resolves the flow issue. Obviously I'll still have codes for the downstream O2 sensors, but I'm hoping that clears up the misfires and pre-cat sensor issues. My future plans are to put sport cats on and extend the O2 sensor cables, but looking to at least get the thing running well for cheap in the short term.



Thanks in advance for any help you can provide.