I changed the upper plastic manifold and gasket along with a lower intake gasket (which now you can get as a metal gasket) on a 98 buick lesabre with 3.8 and 100,000 miles on it. While it was off i cleaned the throttle body with some cleaner and a soft tooth brush it was nasty black inside...turned out like new again....car runs awsum now. Has anyone done tthe throttle body cleaning to there gp's or the lower intake?
