I recently had a check engine light on my 98 F150 /4.6L W / 115K - I performed a tune-up with replacing wires -Motorcraft OEM - Bosch +4 platinum spark plugs. My check engine light did not go out and checked the codes to find out that all indications pointed to O2 sensors - I repaced the passenger side and the light went out. The strange thing is that the truck will not go past 55 MPH before it starts to lose power and pings - Any ideas?

 

The plugs are your problem, go buy original Motorcraft platinums for it.

 

Why don't the Bosch +4 platinums work?

 

bosch double platiums will put u back on a 150 horse power

 

Can anyone provide further explanation for why the Bosch +4 platinums don't work?

 

why cant you just take our advice and get some motorcraft plugs.

 

these trucks dont like anything other than Motorcraft plugs. do your truck a favor and take out the crap bosch plugs and replace with some Motorcraft Platinums

 

Because I broke them. That's why. Now get some Motorcrafts.

 

Now that I have been educated....I will go and buy some Motorcraft plugs..Thanks

 

Nice try, but that's wrong.

If you really want help, start remembering which codes came up, post them, and you'll get help.

I'm inclined to believe the O2 sensor replacement really had nothing to do with the CE light turning itself off as if that by itself cured the issue.

Could the plugs be THE issue? Maybe.

 

I saw the posts for this code, I have just got the Motorcraft plugs and I will install them. Can anyone tell me how many o2 sensors the 98 4.6L has?

 

it should have 4 plugs, 2 before the cats and 2 after the cats. Since your 98 4.6 is the same as my 97 4.6. There is a thread on here with a real good right up on how to change them. I have dialup and it takes forever to search so i hope someone else posts the link to help you out.

 

Because there JUNK. They are a bad plug to begin with,

And Bosch plugs simply do not work well in Fords.

Get some OEM plugs or Autolites.

Also when was the last time you changed your fuel filter. If it is pinging you may be running lean and that could be due to a plugged fuel filter.

 

I've got the same truck and just about the same problem. I've replaced alot of stuff and still suffer from "lack of power". What these guys say about the plugs is true though. I had autolites put in without my knowledge and the truck ran like s***. Replaced with Motorcraft platinums and runs much better. But still.....a power issue. I'm leaning towards cats now being the problem. From what I understand Ford has a lot of problems with the setup on our trucks around the 100k mark. I'm at 135 now, so I'm thinking about ripping those kitties right out. Or gutting them. Not sure how that will effect my O2 sensors though. Anyone get rid of, or gut, their kitties and get around the CEL being thrown??? Of course if you know the cure to our problem that information is also welcome!!

 

You will get a CEL if you gut the cats. Here is a better choice.

http://www.car-sound.com/02product/02directfitCARB.asp