First off, I'm not throwing any codes. It runs strong until the car comes up to operating temperature, then during acceleration it hesitates and then accelerates slower than it does when it's cold. MPG have decreased significantly. It's not smoking, the exhaust does smell rich of fuel.
The radiator fan seems like it's taking a little too long to kick on as well, could just be me though, my temperature gauge reads normal. Idles fine, when it's warm it doesn't idle as smoothly as when it's cold but it's still fairly smoothly though.

I'm running a p08 ECU and a 1-wire o2 sensor.

Any help would be appreciated, I feel like I'm so close but so far away from being finished with this project.

 

I would say it would be the o2 sensor. especially seeing as it is running rich.

replace every 50k miles. the o2 sensor is wearble items that need to be replaced. about the same interval as the spark plugs.

 

I put a new o2 sensor in today. I've still got the same symptoms.

 

does the wiring harness have the plug for the 3 or 4 wire o2 sensor? what is your original trim package on the chassis (hx,cx,vx,dx,ex,si)?

 

It had the plug for the 4 wire o2 sensor. My trim package is DX.