2004 XLT 4WD, 141 000 miles. So far, it's a sweet ride - except the CEL.

I just bought my truck on Monday. Tuesday morning omw to work, the CEL pops up. Aaaagh. Not even thirty miles since buying it!
I checked it that afternoon and learned it gave code 0136 but also showed some of the categories as "not ready". I'm thinking the codes were erased to hide the issues.
A few days later, after 150 miles it's still just throwing 0136. The only category that is 'Not Ready' is Cat, so I guess that figures.

I'm 55, live in Philly and chose the Escape for it's wagon capacity and good reputation. My tools and I often commute 100 miles a day and I need reliability.

I do nuts and bolts maintenance and have done well getting high mileage out of my cars. I've taken several to 245k+ and certainly hope the Escape will do as well... with some help. I've learned a good online forum can be an invaluable resource ; for addressing immediate concerns as well as learning the ins n outs of a given automobile.

So there ya go... I'm a new member, really liking my new daily driver but certainly vexed with this code popping up before the ink is dry. I've read some here all ready, as well at other sites. I do realize there are probabilities (damaged wiring, misfire) as to the cause but there are a number of things that could really be the problem.
I'll be reading and will post any worthy progress I make on my issue.