Ford Rnager O@ sensor

[googlebobber]

I was wondering why my engine light comes off and on all the time for a Bank 2 sensor 1 code p0153

 

[Brian Jasper co. Ia]

From the looks of the tests for that dtc, you might have a "lazy" O2 sensor. If you're over 100k miles and it still has the original O2's, I'd replace both pre catalyst sensors. The after cat sensors only monitor catalyst performance and will not affect engine performance. With the check engine light coming on and going off its acting up intermittantly.
Hopefully you've never used any silicon sealer on the intake system of your engine. Silicon rtv sealers will contaminate and destroy your O2 sensors.