i need to change the spark plugs on my truck(2004 stx 4x4 4.6). i have read all about the 5.4's and there mess with plugs but did not find much on the 4.6. a few people said they can be changed with no problems but i just want to make sure on this. also what is a good type of replacement plugs for this motor? and is there any special tools that will be needed? i read that you need a pretty deep 5/8 socket but not sure if a regular deep socket will work. Thanks

 

The plugs are very deep and hard to get to but you do not have the breakage problem. For best results, go back with Motorcraft.

 

Its a straight forward job, nothing really to worry about on the 4.6's they are great simplistic engines.

When I changed mine the tool I ended up having to use a bit was a compressed air hose. I had to blow out each cylinder before I took the spark plugs out(whoever had the vehicle before me somehow got lots of sand into each cylinder). Now she runs great, just a pain to get those back 2 plugs near the firewall.

Hopefully someone will add more. That is my experience though, and do what Bluejay said.

 

I'd suggest starting on the drivers side first as the front plug is about the easiest on the engine. That'll give ya an idea of what is involved with changing them. I wouldn't call it simple to do but if you have any patience at all and about 4 hours for the first time, you'll do fine. The COPS have to come off first and if the engine has about 100,000 miles on it, now is a good time to change the COPS. Make sure to blow out the plug hole BEFORE removing the plug to get rid of any debris. Take the plug out. If you have a piece of fish tank tubing, it works wonders at removing the loose plug from the hole as they are buried in the head. The new plugs DO NOT require any anti-seize on the threads. Torque to 28 lbs. Make sure to get a generous amount of di-electric grease on the ribs of the plugs before putting them in. Also coat the rubber snorkel on the COPS as this grease is what keeps water from shorting out the COPS. It works as a seal. The COPS are made to self guide themselves over the plugs but make sure you feel the COPS snap onto the plug like a plug wire would. Be careful in replacing the COPS bolt that holds it in place. The aluminum is easily cross threaded. The COPS will still be able to move around some after tightening. They will not be stiff and tight as there is a metal spacer in the mount that keeps you from tightening it too tight. You will not have to remove the injector rail, you can work around them. You'll need several extensions and a universal to do the job and a metric for the COPS bolt. Sorry, but I'm not sure about the size but an 8mm seems to be right. I used Autolite Double Platinums APP104's in mine and they have worked great so far at 25,000 miles. I'd suggest a double platinum plug for longer life regardless of brand. Take yer time and you'll do just fine with it. Here's a pic of how the fish tank tubing works:


It will also help in starting the new plugs. I thought it was much easier to start the new plugs using this rather than chancing a cross thread in the heads using the socket to start the plug. You only get one chance at screwing up the threads in the aluminum- it's gotta be right the first time. If you haven't cleaned the throttle body, you need to put it on the list of things to do. I believe there is a How To in the Tech Articles section of the forums.

 

i have already cleaned the throttle body and MAF sensor. what type of COP's is a good replacement and where is the chaepes place to buy them from?