After a few repairs on this truck (PS pump, cleaned MAF, new leaf springs, new oil pres send unit) It has not hesitated since MAF cleaning and been running strong. Today CEL goes on while running around town. Hooked up my OBDCOM (laptop) and got a single code, P0153 (O2 circuit slow response) (bank 2, Sensor 1) Cold this morn around 30*F but started fine , idle fine, strength of engine, fine. Why this code?
I do have a slow oil leak, valve covers- both...and I think the oil filter bracket O ring leaks some. As I get a strong burning oil smell sometimes. Could the oil be shorting the O2 lead and cause this code?

Thanks for your help.