Quote Originally Posted by Bio248 View Post
not entirely true. i did have a modified narrowband gauge that only read from .800mV and up. i thought it was great for WOT tuning.
Interesting.

Quote Originally Posted by minichopper6hp View Post
not all narrowband gauges constantly move like that, mine doesnt its a summit brand one.
It might be modified like the one Bio mentioned. The PCM is always swinging the AFR while in closed loop mode to verify the O2 sensor is reading as it should. A narrowband that reads the whole range will sweep back and forth with it.