Which plugs are you all running in your 1998 and up Explorer or Mountaineer?

 

Bosch Platinum +4 and I really like them. I have better accelerator pedal reaction now.

 

I have those in mine and other than having less power and worse gas mileage, they're great. I'll be changing to Autolite double platinum soon.
These things fire with opposite polarity on each side of the engine and if you have plugs that all have platinum on the center electrode and not the side electrode, the plugs in one cylinder bank will wear much faster than the other. You will notice that the factory plugs have a platinum electrode on the center on one side and on the side electrode on the other. Different part numbers left and right. The double platinum plugs work equally well on both sides. I found this out after I wasted my money on the Bosches.

 

I looked all over, check the F150 forums especially, and Autolites are NOT exact OEM specifications. Now, back in the day, I don't think there was that much difference. Spark plugs were spark plugs...



If you're buying double-platinums, you're gonna pay for them. Especially Motorcraft, let me tell you -- and they can be tough to find. But everything good is tough to find. Bosch gets terrible reviews, some people have probs with Autolites, nobody complains about Motorcraft.



Again, double-platinums should last you 100,000 miles (the single plats that come stock are rated for only 60,000). Which means, most likely, this'll be the only time you have to do it. So fork over the extra bucks, get Motorcraft, and be done with it. I promise you, once you do the plugs in a 4.0 SOHC Exploder, you will NEVER want to do it again! People have had to pull out their Bosch's or their Autolites, and do them over again... learn from them.



BTW, quick note, pull off the wheel and the whole splashguard inside the fender (it's not hard, 3 minutes) on the passenger's side to get at all the plugs on that side. People have done it from the top, but it's insanely difficult (take a look at that plug in the back, from the top ), and will probably cost you for crazy tools.



In fact, I would do it for the driver's side, too (go in thru the wheel well, i mean). The plugs on the driver's side were no picnic either (I broke off the T-handle on mmy oil dipstick, and jammed a finger pretty bad, not to mention you can't see the holes so you have to use the force to guide the plugs in -- if you go from the top like I did.).



With the wheelwell off, you can sit on the floor and look eye-level at the plugs and the holes.

 

I got my Autolites for 2.99. Motorcrafts would have cost something like 14 bucks a plug. NO. That's ridiculous. They're not that hard to do on my V-8, either, you get 'em all through the wheelwells. Less than an hour to do them all.