Should really check fuel pressure at this point. Or clear codes and try again.
Here's a link to codes, How to and .pdf for diagnostics.
http://coloradok5.com/forums/showthread.php?t=240425
Muddin ? Is your O2 sesnor covered in mud? Not good!
I replaced fuel filter again, with another new one, (i bought 2 the first time)
cleared codes, and drove around for a bit, still sluggish . and when I go WOT. the truck downshifts, and just stays at a high rpm. bogging .
on the way back home from the test drive, the CEL came on, then a minute later it went off.
I checked the codes again, Its still code 12, then 44.
and for the 02 sensor I did what the article says and it seems to be working as intended
**Field Service Mode - This feature allows the vehicle operator to check the oxygen sensor feedback system's condition and verify if the mixture is being controlled to its optimum value for efficient engine operation. To enter this mode, place a jumper between ALDL terminals A and B as in the troubleshooting section above. However, instead of just turning the key to the run position, go ahead and start the engine. At first, the check engine light will flash rapidly about twice a second. This indicates that the system is in open loop operation and that the oxygen sensor has not warmed to operating temperature. A few minutes later, the flashes will noticeably slow down to about one every two seconds or even slower. This indicates the system has entered closed loop operation. At this time, pay close attention to the amount of time the light remains off and the time the light stays on. When the light is on, the mixture is rich. When the light is off, the mixture is lean. As long as the times of on and off are close to being the same, the average mixture is at its optimum value. **
