your temp sendor might be bad,snd that would cause it to send a bad reading or the rad cap is bad like others said before. also you said one of the sensors was bad right? if that was true i would have replaced them all just to be safe... also where did you buy the thermostat? Ive bought a bad one before from advance and i had kinda the same problem as you.. so i just spent the money on a mugen thermostat and it works fine.