Are O2 Spacers required for Max-flo on 986?
 

Hi,
I’ve recently installed the Fabspeed Maxflo Performance Exhaust System on my 03 Boxster. It is great however, since then I keep getting error codes - P1101 [input variables charge measurement] & P1126 [oxygen sensing adaptation lower load, bank 1]. I clear the codes and it is fine for a few days, and then suddenly they are back. I do note that the CEL doesn’t come on. I only know about it as I checked with Durametric after install.
I am running a stock air filter, but not sure of the car’s history (before 2015) I cleaned both the MAF and throttle body. Suspecting air leaks, I checked for excessive vacuum on the oil filler cap, not really evident, but not knowing how long the AOS has been in – I replaced it anyway. I also replaced the O2 sensors (new Bosch). Got a new gas cap too just in case the old one was part of the problem.

I took it to an indie Porsche mechanic and he can’t find fault with the exhaust install or any air leaks either (visual inspection – not a smoke test).
I haven’t seen a P1124 code only P1126 and occasionally a P1101 (once a week).
I have seen that on some exhaust applications that O2 spacer is required. Should that be something I should try? Or given that the CEL doesn’t actually come on (runs smooth and idles fine) – is this a problem I can ignore?

If the code keeps coming back, eventually you will get a cel if you don’t clear the codes. I have a similar problem with my headers and high flow cats. I’m hoping to get my tune adjusted to compensate.

Are O2 Spacers required for Max-flo on 986?
 

Thanks so maybe instead of O2 spacers I look at fuel trim values instead? Although not sure why only bank 1 ??

Yes, might be fuel delivery issue, clogged fuel injector etc. Inspect spark plugs.

OK. I forgot to add I replaced coil packs and spark plugs at last service only 2000 miles ago. I ran a can of injector cleaner through at that time too (do this every service) but I will look at the plugs condition again as suggested.

Got a P1126 & P1133 error today which I believe could be MAF. I cleaned it and re-I stalled it. Cleared codes and went for a long drive. So far so good. I might have to get a new one before it fails completely.
Thanks for the advice.

All the better if all the plugs look good you must have crossed some of the coil wires.