Is there any way to test the Ignition Coils to see if they are working properly? Here's the issue, I am getting engine knock when climbing a hill or accelerating hard on the highway (sometimes). I was told that this is either the Octane gas I am using, which I usually use 91 but have been using occasionally 89, or it is the Ignition Coils. Before I spend 500 bucks for coils, I wanted to make sure that is the problem. To start off I have been putting 91 Octane and I am on my second tank but I wanted to ask this question if there was anyway to test the coils, maybe with a voltage meter or something? Thanks.

 

start car...mental note idle...shut-off car unplug a coil....start car...note any change in idle...repeat lather rinse for all six....the one that doesnt change ur idle when unplugged is bad...but it just sounds like fuel starvation how much gas how steep of hill....

 

How long were you using 89 Octane? That could be the cause of the knocking noise since our Max's require high Octane 90 and above. As far as the coils, you can hook up a DMM to it and check the resistance of each pin to see if they all compare to be the same within each other.

 

Thanks for the info..As for your above question, WOT and the hill maybe 30 to 40 degree grade (I'm guessing here).

 

Maybe 2 tanks of 89, then I would put 91 and so on.