Limped my '97 home the other day after a week or two of deteriorating performance. Finally took a close look, and the 2-5 coil was lighting up like a Christmas tree.

...and its 2-plug terminal was completely corroded and carboned up.... even the whole length of the porcelain was completely black....

After swapping it out for equivalent, overpriced NAPA item, replacing the wiring and new Iridium sparkplugs, it is smooth as silk....


But in the course of all that, I found that the 4-plug terminal is ALSO totally corroded although not as bad as the 2-plug was... while all the others are "shiny".

Is a corroded coil terminal telling me anything in particular??? I haven't swapped that coil out yet, 'cause car seems really smooth right now... I just cleaned the terminal a bit...

clean the terminal and put a bunch of dielectric grease on there.