I've got a 1997 F150 XLT, 4.6L. For a while not I've noticed that going up certain hills I've had a major loss in power, to the point to where my truck would have to downshift twice just to make it up. And this is with starting at the bottom of the hill at 55-65mph. So I desided I'd replace the plugs and wires. Well, I'd never actually taken a look at my plugs to see how difficult it would be to replace them. I've replaced plugs on many cars before, ranging from little 3-cyl Subaru's to 8-cyl F350's. But I'd NEVER seen anything like what I found under my hood. It scared me at first... and it still does . But I knew it would cost me a small fortune to go to a mechanic, so I figured I'd just do it myself. So I searched the net for some resources for replacing the plugs and came across these forums. I searched through them and found amazing advice on how to get it all done. And so for that, I thank all of you! Took me around 3 1/2 hours, but I got all 8 plugs and all 8 wires in there, and MAN does she run better! So for any of you out there that are hestitant about doing it yourself, just follow what everyone on here has posted and you'll get it done in no time!

Just figured I'd post this, letting you know that your forum helped me a lot. So thanks again!

-- John

 

Once you've tackled a plug replacement job on one of these mod motors it's much easier the next time around. You'll have more confidence and not be scared poopless when looking into the engine compartment.

 

I just had the same experience here. The manual says 90k miles on a set of plugs. I just turned 80K and thought I would be a bit pre-emptive. I've got a 2000 F-150 4.6L V8 with the COP and I've never worked on them before. I'm what you call mechanically inclined, not automotively inclined. Well, I picked up a set of Bosch Platinum +4's and a new air filter. The total came to $73. I was going to have Ford do it (it looks a bit intimidating), but they wanted like $400.00 just to change the plugs. I took my time working slowly and deliberatly, one plug at a time. I pulled and cleaned each coil, then replaced the plug and the coil. The only coils that gave me any trouble were the two rear coils on the drivers side. Other than being a contortionist, everything went fine. Total time, including a coffee brake between doing the passenger and drivers side was about 2-1/2 hours. I could have saved about 10 minutes if I had realized that the power steering fluid reservoir was in two pieces so you could get to the first coil. I was trying to un-do the whole thing.
Surprisingly, the plugs I took out still looked pretty good. All had a nice tan burn color and were still gapped about .055, one at .060.
Based on my Anterior, Side mounted, Sit-o-scope, the truck seems to perform and accelerate better. I imagine new plugs will do that, and hopefully my mileage will get back up to what it used to be.

 

glad it was an easy fix!

 

If By No time you mean three and a half hours

Haven't made it around to changing mine myself, (5.4) But it does look intimidating. I had the 60,000 Mile checkup done around 20k miles ago and they said they replaced them with Bosch 4+Plats (At the time I didn't know Bosch's and F150's were a no no) But I didn't notice any change in performance. I've always thought they just left the other one's in there and charged extra for the 4+ plat plugs since they look like a burden to get to and figured I wouldn't check.

Guess it worked for them, regardless.... I think it's time to check.

 

I've been working on my own cars, trucks and bikes for 20 years, but had no desire to touch anything under the hood of my '99 f-150 5.4... When she decided she didnt want to climb hills anymore, I searched the internet and found these forums, and with the info I found here, I managed to get my plugs changed and a defective COP replaced in about 3 hours or so...

She runs like a dream, and my gas milage is certainly better... All the plugs were a toasty tan color, but the gaps were all around .065-.070.