Dont know if you guys knew/know, but there is a tester available thru Home Depot for checking these coils. Ebay wants $50 for a chinese, and 3 digits for english manuf. We watched the youtube video using a Waekon tester which has variable sensitivity adjustments. Anyhow its only about $90 delivered free. Son just ended up replacing 2 cops on his 5.4 so he wanted to test but no one had any testers, just readers for codes. These do not require removing the coil to test.

Someone here posted they bought cheap COP's from rock auto, I see they supposedly have high output for around $20. Anyone know if they are any good?

 

Stick with OEM Motorcraft coils. Typically those who replace with aftermarket cheap coils are doing the same a year or two later.

Also you really should only replace the failing coil. There isn't a need to replace all at the same time.

Boots and springs should be replaced though. Think about installing a O ring in the channel of the coil to better seal it as well.

https://www.ford-trucks.com/forums/1...s-the-fix.html

 

The Wakeon COP testers have been around a while, prices all over the place for some odd reason. I almost bought one, the only reason I didn't was the prices too quickly escalated for the same damn thing.

To my thinking COP's work or they don't, when failed the PCM with OBD-II catches it so that sort of tester didn't make a lot sense to me owning one. Despite them supposedly being able to show how balanced the COP's are to one another if that level of testing is required an automotive oscilloscope would be the better choice diagnostic-wise, not something for us average DIY guys.

As for cheap COP's---DON'T! I'm one who fell for the cheap thing and just as Bently_Coop says I was replacing them again one-by-one within a few months. Since then on another van I've replaced two more but used NAPA's good stuff, about $50 each. Motorcraft or NAPA, my only choices in the future.