my 95 yota has been idlein like crap here lately, but runs fine. i assumed the TPS, but took a look under the hood today. i replaced the rotar button and dizzy cap a few weeks back to see if that would fix it. negative. new plugs and wires abotu 10k ago. anywho i grabbed the coil wire on the dizzy cap and heard a crunchy noise. looked at it, and the rubber boot is melted, and the metal inside it is corroded and broke off. pretty sure this is my idle problem, but my question is, how did this happen? also, the prongs in the cap is already black after a few weeks, and so is the rotar button, once again, why? is is a sign of a nother problem?

 

coil wire, as in the wire coming form the ignition coil and going to the center post of the cap?

they're just like a spark plug wire; they go bad over time too and need replaced, and should be replaced along with the rest of the plug wires too. when's the last time you replaced it? do you know how old it is?


also, if the wire was loose fitting inside the cap, it will cause arcing, and arcing causes excess heat (thus the melting) and corrosion

 

it was replaced with new plugs about 10k mi ago. but the rest of the wires are fine?