[Zoowackery]

This is what Autometer said:

The PT Cruiser's factory O2 sensor is not compatible with a narrowband air/fuel gauge. It's actually a bit of an anomaly as far as O2 sensors go, as it shares some characteristics with a wideband O2 sensor, but reads like a narrowband. Because of this,it actually won't work either way. You will need to add a weld in bung to the exhaust system (pre-catalyst) to use a gauge like this. On a narrowband unit, you'll want to use our 2244 kit (although most factory narrowband O2 sensors will work). On a forced induction vehicle such as yours, you will be much better off using a wideband like the 4378. This will give you realtime measurements of the mixture. This makes it an
invaluable tuning tool for setting fuel/boost curves. The narrowband units serve as a good warning when the vehicle is about to go lean, the wideband shows you what's actually going on. Hope this is helpful, let me know if I can be of further assistance.

Best regards,

Joseph Mills
Auto Meter Products, Inc.

Hope it helps.