can your EGR valve "stick". i already checked the system and it all checks out. selinod works egr valve holds vaccum and moves like its supposed to. can my egr valve stick open when it gets hot? car doesnt act up very often/regularly but this is starting to drive me nuts. tach will fluctuate very badly and car will missfire. if i allow the car to idle for a few minutes it smooths out and runs good again. this is become a real PITA, i hate trying to diagnose something that's so intermenint. i also have to make a trip from buffalo, ny to dayton ohio, about 400 miles each way and im worried about the car. i dont know whats wrong with it and i dont want it to break down 400 miles away from home. i drove the car about 250 miles the other day to go to a funeral and it ran like a dream. any thoughts about EGR codes or what a EGR system will cause a car to do when acting up would be appriacted. i wanted to add 1 detail, if it matters. why doesnt the EGR valve hold vaccum with the engine running*using hand help vaccum pump*. i get a very slight rpm drop when i use the hand held pump but it is barely noticable(will not hold vaccum on a running engine only on when engine is off).

 

What year? What engine? What fuel system?