akdoggie

I know its the CAI. I experimented with a BBK CAI before going to the JLT. I was just stating that I put it all on at one time and liked the response. More so with the JLT set up. The difference between the SD and Motorcraft is very minimal, but since I got the coil and wire package from my daughter for a Christmas present last year, it was the least I could do to try it. It's been on since then, and so far so good. Like I said, I like the power curve I've found, so I'll leave it the way I have it now. If I find something that works better, I may change to it, but overall, I have no disappointment at all with the set up I have right now.

JimC

You put all that on at one time, so how do you know that the screamin demon did anything for you? And Nuke and 157 are right, the tune did more than anything else that was done. If you want to know what a mod does for performance, only change one thing and see what happens - otherwise you don't know what a single change did for the car, or if it was worthwhile.

Arkansas V6

Put the plugs, new wires, and the Screamin Deamon coil pack on and i am very happy, cranks quicker, idles great, and acceleration is very smooth. Everythings working fine and i am very satisfied

akdoggie

Glad to hear that I wasn't the only one happy with the way the 4.0 runs with this set up. My idle was definitely smoother, but again that could of been the tune. Im just glad you are happy with your purchase. Mine was a gift, so you know I'm happy with it.

Nice Pony

I have had a Screamn' Demon coil pack on my 4.0SOHC for over 100,000 miles with none of the reported issues. Must have got a good one.

That said I did experiment with swapping back and forth with the stock one with brand new Autolite 5143 Copper Core sparkplugs just to see if there was any noticeable difference and there wasn't any at all. So basically a waste of money that could be better utilized on another mod. Also the spacing on the six connector towers are not evenly spaces like on the stock coil so can make getting the wires installed correctly tuff especially with fatter aftermarket wires.

Those that seem to get smoother idle and more performance will get the same thing with just a sparkplug change. The stock plugs that come in these engines will not go anywhere near as long as they claim. I pulled mine a 30,000 miles and they were Motorcarft platinum and they were totally shot and the gaps were all over the place. This was before I had done any mods to the engine like the X-Charger or CAI.