Unplugging it will prevent exhaust from reentering the intake, so that will work and some do and some don't throw a CEL based upon the year of truck and the PCM strategy. You might also want to block off the EGR cooler, so the hot exhaust gasses don't get dead headed due to the closed EGR valve and heat soak the cooler. These EGR coolers are notoriously weak, so you should consider blocking them off.
Originally Posted by icedevil
call me a newb if you want what is the purpose of the egr? what does it stand for and why do people block it off? sorry, i dont mean to hijack the thread
EGR stands for Exhaust Gas Recirculation, which means that some of your exhaust is reinjected into your manifold to reduce emissions. People block it off because the EGR valves get coated in soot and stop working properly. The EGR valve is commanded open only when the engine is operating at a certain level, not all the time, so when it gets stuck open, the engine starts to run pretty poorly (surging, stalling, generating black smoke, etc).