Whats the very very first sign of a failing coil pack that you wouldn't notice in performance... any particular sounds, etc?

 

Hesitation, bad idle, the engine misfires and kinda jumps

 

A CEL? lol, performance under hard acceleration will definately be noticed. I went with mitsubishis as opposed to hanshins when i replaced all 6 of mine. seems to be the weak link in the maxima.

 

i took a couple of plugs (ngk brand new)out and tested the coils and the sparks dont seem that bright at all... i mean i did a tune up to my moms foci last night and they arced like crazy... but in my car u can barely see them... but i dont really see a performance loss... whats up with that?

 

Would a single audible "thump" in the exhaust be a sign?

 

Yes that would indicate a miss

 

Ok so say I hear this single thump only once when I turn the car on... how do I test for the bad coil?

 

Yah, I'd like to know as well...

 

check the ecu codes