Coil testing

[Dr Dave]

Hey guys happy fall. I have some questions I have been getting frustrated with. I thought that when a car comes in with a misfire ,if the coils are easy to get to that running a amp ramp test would avoid me some embaressment if I found a bad coil before the tune up if needed. Well on a transveres v6 I ramped them from the fuse box by left bank/right mank. they all looked the same -but found 1 bad coil in the end thanks to the code .The a 1999 passant I couldn't get a pattern - found the ic modual was bad. but more recent a 2016 compass 2.4 -all the coils looked the same after the tune up still has a mis and swaping the coils showed the mis followed the coil. so whats the deal swapping the coil is better that the scope ? Is there a better way to labescope coils ? Iam I doing something wrong ? is my scope lying to me ?

[greasybob]

Snap ON does have an assortment of coil on plug (COP) inductive pickup adapters that pickup the secondary waveform. It's an alternative but I rarely use them.

[Dr Dave]

The adaptors are like the cone of silence on Get Smart tv show they rarely work. I really want to get to the nuts and bolts of how I get a what I think is a good amp ramp pattern that looks like the rest and swap coils and clearly the coil was the issue . What part of the pattern do I need to be schooled on , And is it possible that the amp ramp can in fact miss a bad coil ?