Distributor Cap Keeps Getting Eaten

Thanks in advance for looking at my problem. My Durango's has been having spark problems this week. It wouldn't start this weekend (it would turn over, but not start) so I changed the cap, rotor and plugs. The contacts in the cap had some arcing on them and the button on the top inside of the cap (coil contact) had been eaten away a little bit.

Replaced those parts, drove it about 30 miles, and it wouldn't start again. I took the cap off and found the same problem, white lines on the contact and the top inside button eaten. I put the cap back on and it fired up again, then yesterday I replaced it with a better cap, rotor and plugs.

I've been told the crankshaft position sensor is a culprit on this truck and I should try that, but would that cause the "eaten distributor cap" problem?

Thank you.
'02 Durango R/T 5.9 56k mi

You could have bad plug wires. Replace them also.

Well, they only have 10-15,000 miles on them right now. Can they go bad that quick?

I couldn't imagine the spark plug wires would cause the distributor cap to malfunction like that, because the distributor cap transfers the spark from the coil to the wires, and not vice versa. However, I don't know much about this stuff, just guessing.

If the resistance in the wires is high the voltage and amps will be higher and cause more metal transfer in the cap. It is like welding. Also put some dielectric grease on the rotor tip and cap terminals. It will help.

Thank you everyone for you help. I changed the coil, cap and rotor today. I learned how (kinda) to use an ohm meter. The original coil was at 18 (or 19,000, I'm not positive how to read it) and the new coil was at 12. I figured that was way too much resistance for the original coil so I replaced it. The wires ranged from about 7 to 9, I compared them to new wires that I bought from NAPA, and those ranged from 5 to 7 (depending on the length). I decided not to change the wires because that didn't seem like too big of deal to me and I would like to keep the $50 they cost. The cap and rotor are OEM Mopar, so hopefully I'll be okay there.

Once I get my brake problem fixed (sticking calipers) I'll do some driving and let you know how all the ignition repairs went.

Thanks again,
J