i have a 89 astro van that smokes a lil not to bad but i feel the power of the motor has goin to shit with it the way it is and i was just wondering if it is worth it to change them or if there is another way around this smoking prob ?? mechanical side of it is no prob but i have never done it and was wonder the best thing for this problem i have its v6 4.3 and the motor has 190000 miles on it