Anybody have any good or bad experience with the Bosch Platinum+4 spark plugs??? Are the stock plugs the best?? Also, whese can I find a definitive manual on how to replace them. Thanks!

2000 F-150 XLT Supercab
5.4L V-8

 

I put Plus-4s in my 97 4.6l about a year-and-a-half ago (45,000 mi). I now have almost 90,000 miles on it and the plugs have been just fine.

BUT...I don't think they gained me any HP or mileage. It did idle smoother when I changed them, but ANY plug would probably produced those results.

What I'm saying is that I don't think they are worth the $$$$$...like $5.99 each here in Roch, MN. I think any good platinum plug would work just fine. When I replace them in the spring, I'll use something cheaper.

 

Had a Ford Aerostar 3.0L minivan before my 1999 F150. Tried to put Bosch Platinum plugs in the Aerostar and couldn't. The Hex nut on the plug was half the height/thickness of a motorcraft plug. My sockets would not go deep enough to install the Bosch's, put new Motorcraft plugs in just fine.

Glad to hear I could put Bosch's in my 4.6L if I wanted to. I thought the 4.6L was a 100k tuneup engine?

 

Sounds like you got the wrong plugs, as they should have been the same hex size. Not to rant here, but I don't know how many times I've gone into the parts store and have been given the wrong item because the doofus behind the counter either can't read or follow a line item across a page or whatever. The last time it was shocks...in spite of the fact that I TOLD him it was for a 4 X 4, he gave me the ones for the 2 X 4. Now I always verify it personally before I place the order.

Beyond that, yes it's certainly possible to put Plus-4s in a 4.6l, but it's NOT FUN. Do a search on this topic and you'll see why. And anyone who kids themselves into thinking plugs last 100,000 is hallucinating. I suspect that they say that because they are such a pain in the *** to change. I think every 30,000 miles is more realistic.

But if you can change plugs in an Aerostar, you can probably handle a 4.6l

 

I hate to burst anyones bubble but the spark plugs can and do last 100k without too many problems. Otherwise, there would be nearly no benefit to using platinum plugs. Heck, I didn't change the plugs on my truck until I had nearly 112,000 miles on my truck, when the truck had to visit the repair shop for new tie rod ends. Sure the plugs don't come out looking like new, but they weren't bad either. The gap was off a bit, but nothing that was unacceptable. After replacing the wires and plugs, there was no change in performance, etc... I did note a drop in fuel mileage of almost 1 mpg, but that may have been due to other factors as it has since gone away. They were replaced with motorcraft platinums and oem wires. Now I'm down the road 30,000 miles later and I have no intentions of changing the plugs anytime soon.

In any event, its your choice. I just don't feel changing them that often (30,000 miles?) is necessary if there aren't any problems that can be traced to the plugs or wires. My two cents...