[fireplow]

This could also be a vacum problem also(getting to much air thru a vacum line) use some carb cleaner and spray around the vac. line and lission for a change in the sound of the motor (even a slight change). The EGR valve could also be bad allowing to much air into the system. Locate the valve and spray carb. cleaner around it also. Take off the vacum line and spray some into the line going to the EGR valve. (you will need to cover the line going the intake with something) If you get a change in the sound of the engine go from there. NOTE if it is the EGR valve DO NOT get the valve from any other place than the dealer!!!!!!!!!! the others may be less money but won't last. you can goto Autozone.com and look at an EGR valve. hope this helps.