Form another board that I visit I found that you can clean your o2 sensor if it's sluggish/slow...

Go to the auto parts store and get CRC Electronics Components Cleaner, pull out your o2 sensors (front only unless you have a rear o2 failure) and spray them liberally on the sensor end (which goes into the exuast stream) with the cleaner. let it dry out for 10 minutes or more and DO NOT USE COMPRESSED AIR to speed things up. Once it's dry, pop it back in and if you have any codes, reset your computer (disconnect the battery for 5 minutes or more) and take it for a spin.

This should help. I do this to my bmw M3 and it works great. An o2 sensor that was causing surging is now fixed (M3) and it runs great. No CE light, no codes....

 

I did that with my Ram too Steve lasted about 500 miles then CE light came back on, same code, cleaned it again, another 500, same code and CE came back on. Finally just went out and spent the 75.00 cause my *** was getting sore from crawling under the truck

 

your o2 must have been too far gone then. I had a similar situation with an o2 for the m3 and a 2nd cleaning took care of it. the 1st time around it thru a code, then no codes. anyway, a $5 dollar can of spray is a lot cheeper than a $75 o2 sensor... if it works great... if not, you have a can of cleaner