[Catterman]

I never understood this one, does it just recirclelate the exhaust gas back into the combustion chamber when cold? What are the differences between the EGR valvle, EGR vacuum solinode, and the EGR position sensor?

now that I have cleaned my EGR ports, my check engine light comes on (with code 12) after I have been driving for a few miles, and then will go off a few miles later and not come back on again unless I start the engine up cold.

Thanks, this is a great site.