need help with a vag code

[slo1ate]

I ran a scan using an ebay cable and the shareware version 409.1. I got the code "16517 - Oxygen (Lambda) Sensor B1 S1: Response too slow...P0133-002 Lower limit exceeded - intermittent."

I'm running the GIAC BI file with genesis 380cc injectors, hitachi e coilpacks and BKR7EIX plugs, gapped to .028. I've been having trouble under hard acceleration, I get some stuttering. At first I assumed it was a bad CP, and I thought the scan would confirm that and tell me which one, but now I'm not so sure. If it was a CP, wouldn't I get a misfire fault code? Or maybe the unregistered version won't show that code?

I don't know whether to try changing the plugs, or replace coilpacks one at a time, or just take it in. I won't take it back to my tuner since he screwed me on a totally unrelated deal. I do have a good indy shop, but they're not a GIAC shop and I'd like to save the $90/hr in labor if I can.

[slo1ate]

Just to clarify, I know the code says O2 Sensor, but I was wondering if there was any more info out there. E.g., does that code get thrown when it's running too rich or dumping too much gas and putting out the spark? Or, does it just mean an O2 sensor is going bad.