Background
My 05 Lariat was having shaking problems when accelerating, so I took it to a local mechanic that seems reputable by everyone around me. Oddly enough, the diagnostic showed nothing whatsoever with the engine, only showing a lean code and a "oil too hot" code, which was strange; even to the guys at the shop. Eventually I informed them of the real problem and reason as to why I had brought my truck in and, after going on a test drive with one of the mechanics around town, I was told it was an ignition pack that was responsible for my truck shaking in overdrive.

So I thought to myself, alright, that's something I think I can do. As long as it's not those infamous spark plugs, I think I can successfully change out the ignition coils. So, I buy the Motorcraft DG511 coils and think "alright, 1-2 hour job. Let's go."
Well, needless to say, it wasn't a 1-2 hour job. It wasn't even a 1-2 day job. I've been having difficulties with my truck and have only managed to replace a whopping total of 3 ignition packs on my truck. Coil 1, 2 and 7. Now, why did it take so long you might ask? Well, it lies into why I'm coming here for some help right now and why my truck still isn't back in driving condition after 5 days of working on her. Firstly, about 2 of the ignition connectors broke (3 actually, but I forced the third one all the way down and angled it under some cables so it wouldn't shoot out) and I had to use a quick splice tool to get new connectors that worked and managed to grab onto the coil.

The Problem
However, the same story has happened since that fateful day that I decided I would take on this challenge; my truck shakes wildly on start up and struggles to reverse (does a bit better on drive but not by much.) At first I thought it was an alternator/battery problem, since the moment I tried to reverse I got about 5 feet before my truck's steering siezed up and the truck turned itself off as the check battery signal light came on my dash. However, I later realized I had my emergency brake on and forgot to remove it (truck hasn't turned itself off since). But, she still has troubles when reversing. If I reverse in a straight line, the truck is relatively fine but the moment I turn the steering wheel, the wheel locks up for a bit and she begins shaking wildly again. However, if I have her in drive then she drives...without much power. I have to lightly tap on the accelerator little by little, and even then she might start shaking.

So, I had enough and popped the hood while she was still running and I check what I assume was the problem. It couldn't be the ignition connectors. I already spliced the only ones I touched minus the third one. Now, it could be that the third one is causing problem but... surely not? Now, I will get to it eventually and splice a new connector, but surely something temporary wouldn't cause my truck to violently shake at idle? No, it can't be. It has to be the coil that has been the bane of my existence and the one that's caused this task to be delayed for so long.

The main culprit
Ignition Coil 1's bolt. This bolt right here has nearly made fight the other residents at my apartment complex. From the moment I replaced this coil, I've had nothing but trouble with the bolt. My problem was that the original bolt would only screw back in about 3/4 of the way before it was stuck in a endless cycle of constant spinning while the coil remained loose. At first, I thought the threading on the bolt was stripped, so I grabbed another stock bolt from a different coil to test it. Nope. Same thing. So, it must be the threading inside itself, rather than the bolt. So, I thought I would go to the Home Depot with a friend and get another similar bolt that was much shorter. Now, I couldn't find a 7mm head, so I had to settle for an m5 (8mm) bolt with the same threading. Just so you're sure that it isn't the bolt's problem, I ended up using the same m5 screws on both Coil 1 and Coil 2. Coil 2 fits perfectly and snug. However, coil 1 is still a culprit. The new bolt was shorter than the stock one, so as to test the theory of the inside threading being stripped further down. Somewhat correct. The newer bolt definitely got the coil a bit tighter than the stock, but still not the snug fit as all other 7. And as I suspected, when I popped the hood, it was coil 1 that was shaking madly and wildly while all other coils were stationary and tight.

As a last Hail Mary, I'm buying another bolt that is shorter than the other two (stock was about 30mm long, Home Depot bolt was 25 mm long) that's about 20 mm and praying for the best. However, if that doesn't work then I'm open to any ideas that you guys might have. (might concede defeat and just have her towed to my mechanic for a professional to fix.)

 

buy a stud that is about 1/2 inch too long and put epoxy on the stud and screw into the hole. Let it set, then install the coil and use a nut on top to hold the coil down.

 

You could use the stud Idea . Or Fill the hole and carefully re drill it ,you can re-tap it if you like, with care . Some will use jb weld - anything that would be tap able , make sure you use a matched drill bit to the proper tap . I hope you are soldering in new pigtails and heat shrinking them . I have observed that salty northern engines get a lot of rust on these cop bolts and a little anti-seize on threads helps for the next time you remove them --- its just a plastic manifold . Its best to keep the hardware the same from cyl to cyl .it can get confusing . Don't over torque them -- I use a 1/4 inch socket and keep my hand on the head not using the leverage of the handle . Factory oem coils rarely fail they just get corroded ,clean all contatcs good and use contact cleaner . My coils are orig at 206k miles . Wholesale replacement is not a recommended thing . In many cases you are changing out $ 60 each coils for a set costing $60 --doesn't that make you think --whoa.
But you are correct you can't have this cop loose, it holds spring to spark plug tension . It will cause misfires .