First and foremost, this is my first post; I'm not sure if this is the correct place to post this, if it is let me know.

Okay, I have a 2008 Ford F150 FX4 5.4L V8 3V that I bought about 2 years ago now, it has 114,451 miles on it and it isn't running like it used to. I've done most of the work on my truck and it has mostly been suspension and brake work though.

I recently changed the spark plugs and ignition coils with Motorcraft SP515 plugs & MSD Street Fire Coils and managed to remove all 8 without breaking them, I was pretty proud of that. However I believe I made a newbie mistake, I did not torque them to the specific torque spec, and put aluminum anti-seize including on the threads, which I later read is not recommended. I then drove about 150-200 miles, and by then my truck was running really bad, ticking noise, stuttering acceleration, and crazy shaking when I would go faster than 60 mph. I re-torqued them, once again not to a specific spec but I believe I may have torqued them too tight. As I was doing that I noticed I may have broke the vacuum actuator line that runs to the solenoid on the passenger side firewall when I changed the plugs, as a quick fix I used windshield washer rubber tubing to reconnect the vacuum lines and then I cut a piece of tubing from a plastic pen to slide over the rubber hose for extra strength and actually fit snug.

I've been driving it for a while now and it is wasting so much gas, engine doesn't feel like it has a misfire, but it does have a shake to it at idle and also feels forced when I'm going over 70 in the highway, but it used to go 85 easily. The tires and engine are pretty loud, the engine sounds like it's struggling to get air, and the tires have a really loud humming and also sound like it's flat but i checked the tire pressure and they're all around 40-50 psi. They're mud tires and I know they're louder but it's excessive now. It also leans a little to the left when I'm on the highway, and a little bit of grease is oozing out of the lower ball joint on the driver's side. The truck's suspension rattles more than it used to when I drive over bumps and potholes. It's also blowing more smoke from the tailpipe at a cold start, not too bad but still concerning.

So I have a couple questions/remarks:
1) I believe the tire noise and rough suspension can be the ball joints, and was wondering if the broken vacuum actuator lines may have broken the 4wd actuator. Also if maybe it could be a wheel bearing being worn out or broken. Plus if I replaced the ball joints and 4wd actuator I would also do the wheel bearings since I would be there already. Then getting my tires balanced and an alignment. Good/bad idea?

2) For the rough idle/loss of power and horrible gas mileage, I believe it may be a clogged catalytic converter because I did drive my truck with bad spark plugs for 2 months and then drove 150-200 miles with probably loose plugs. I am planning on changing the exhaust manifolds with Banks Shorty Headers and Flowmaster direct fit catalytic converters. I'm also planning on replacing the spark plugs again and torquing them correctly and using nickel anti-seize and not on the threads. Would this be a good plan of action?

3) Now, although I'm pretty sure this is not what I have but a hypothetical that could be possible. I'm wondering if I may have cracked my head since I may have tightened my spark plugs too tight, and the smoke coming out the exhaust may be coolant that is leaking into the combustion chamber or if it could just be the clogged cats. I'm debating if I want to do compression test and leak down test to see if I have an internal coolant leak, but I'm 80% sure that isn't the case because my coolant level has not decreased since then.

4) If I should do a compression test, how do I disable the fuel pump on my F150?

I know this is a super long post, but I'm trying to fix this soon since it is my only truck. Plus our family's backup car (95 blazer s10) has a leaking radiator that I'm going to replace one of these days. Any useful input would be appreciated, thanks.

 

It's okay to put anti-seize on the spark plug threads. I doubt you overtorqued the plugs to the point that it could cause a problem.

Folks on this forum don't like MSD COPs. They usually recommend you buy motorcraft.

A muffler shop should be able to check the cats to see if they are plugged for not much cost.

Ball joints don't usually cause any noise unless they wear to the point that the tires were irregular and cause noise.

It sounds to me like you may have a too vivid imagination about how many problems you have. I could be wrong.

 

Oh okay, I'm to get Motorcraft ones then, but yeah I knew i couldn't have cracked the head that easily. But okay cool, I'll take it to the muffler shop get the cats checked out and then maybe just change the ball joints and see what happens. But thanks man.

 

Recently I change the plugs on my 2006 king Ranch Expedition. I got all out, but one broke on the driver side. Cylinder 8. But I used the Ford tool, it came out clean.
The only problem I have now is cylinder 7-8 won't fire, I have tried everything from new boots to old. I even went as far as trying one of the old spark plugs. I check the harness, do the harness on the trucks ever go bad like the connection broken inside the connectors?

 

Did you ever get your issue sorted out?