KA24E burns up rotor caps

[danullom]

My 1990 240SX KA24E daily driver has started eating rotor caps. I first replaced the spark plugs, wires w/dielectric grease, cap and button about 2 years ago when it started to idle extremely rough. That was good for about a year, then I had to replace them all again, but I only got a few months out of it. I begrudgingly replaced them all again and two weeks later the car started idling rough/dying on me again. Ingrate. So I tried just replacing the rotor cap and it again runs flawlessly. My avatar is a picture of a contact from the last burned out cap.

An additional symptom is that the car has started blowing the fuse on my stereo more and more regularly. The battery is only about 3 months old. The ground wire shows very low resistance to most points but I am not against a bad ground still being the best diagnosis. My only ideas now are to replace either the ignition coil ($) or the alternator ($$).

Any advice would be greatly appreciated.

[the converted]

That cap looks pretty good to me. Your coil is probably starting to go.

[danullom]

Thanks, I'll will try a replacement coil and report back.

[danullom]

I picked up a used coil for $25 and installed it. I'll have to wait for 2-3 weeks before I know for sure but the car runs more smoothly now than it has for a long time. I think that did it, thank you!