I have been having hesitation problems when accelerating on my 93 K1500 Suburban. Hoping to correct the problem, I inspected the distributor cap and rotor. When I pulled the rotor off off the distributor, the distributor shaft was rusty as was the contacts on the rotor. I do not think that is normal but what would cause this and more importantly, how do I fix it? Is it necessary to remove the entire distributor and inspect for rust?