I got my Cltuch replaced 4 days ago and My check engine light went on as well - I went back to the shop and they said its my O2 censor. They are not sure why it keeps failing, but it could have been damanged during the process.
I have the gov in still and I've gotten my taco up to like 130MPH at about 4500RPM and thats where it kicks in and doesnt let me go any faster, I dont think we really need to take it out but it would be fun to be able to get as close to red line as possible in 6th gear with out blowing our shit!