6420 JD loss of power
 

I had my tractor in the shop a couple weeks back electrical problems caused it to blow a fuse and die. 2 weeks later the jd people found it was a temp sensor that was shorting out.. before it would run labored untill it warmed up and just like u flip a switch it would open up and run like a top. the way i understand it is that switch opens up an exaust flap that impeeds the exhaust flow untill the motor warms up. Now that i got it back the tractor seems to have noticably less power all the time.. Does anybody know anything about these tractors, or what could be happening? Thanks