emission control causing rough idle?

If you decide to install a new EGR valve, you can update to a more advanced type that is a direct bolt-on. Standard #EGV490; RockAuto's got them on sale for under twenty bucks and you can knock that down further with those 5% RockAuto discount codes that are always floating around. This valve has a backpressure transducer that modulates vacuum to the EGR valve to match EGR flow rate better to the engine load. Takes a smaller bite out of driveability than the non-transducer type valve.