Sensor swap and gas mileage

[Black Sun 5.0]

I just had my O2's, which were dead, and mt ECT replaced. I also put the stock T-stat back in the car. Suddenly my gas mileage appears to have taken a dump. I replaced these parts to fix this issue. Anyway, my question is this: does the computer on these cars take time to 're-learn' all these changes, and how long should it take?

 

[84blkstang]

yea it does take time to relearn, just unhook the negative battery cable for 10 minutes or so and it should relearn

 

[88stangmangt]

you should gain more MPG from clean/fresh o2's

 

[Black Sun 5.0]

Well, that was the thing. I replaced the sensors, which were only a year old, and now the mileage tanked even worse. I'll disconnect the battery later when I have a chance, thanks.