Originally posted by gearhead:
If none of that other stuff works, your EGR valve may be stuck open. That would cause rough idle because it's supposed to be closed at idle.



sorry to keep this thread going, but.....

just finished replacing my spark plugs, old ones looked pretty bad. BUT...prob still exists. Ive narrowed it down to the secondaries, the car runs fine until i hit 3800 rpms or whatever it is. The engine tone goes from normal SVT exhaust to a deeper, not good sounding tone past 4000 rpms. Is this symptomatic of secondaries that arent opening?

98 SVT #1652 of 6535 My SVT "If everything seems to be going well, you obviously don't know what the hell is going on."