I have a 95 5spd 16V tracker EGR tubes are clean and I believe that it is working properly.How ever I get the EGR code 51.I can usually tell when I wil get the code or when it will stay or go out.If I start it when it is cold sometimes I will get a big puff of stinky smoke if I do I know that my CEL will come on usually sometime in that trip. Then  if the light is on and I go start it when cold and it starts up with no smoke I can pretty much be sure that the light will go out sometime in that trip. I have tried the search here and one post says that the EGR temp sensor will set it off where is it and how can it be checked?The same post said someone was blocking thiers off is that possible without the light being on all the time?I have 2 1/4"  exhaust all the way back no cat and before you say it's my exhaust. I had this problem before I installed my exhaust so I'm pretty sure it has nothing to do with my problem. What sensors need checking and what tips or tricks to fool the ECU so I can run without my light being on?Any ideas or input would be appreciated !
Thanks!