The plugs will last longer, but the tip is getting burned off, so it will use more fuel to fire. They still work, just not as efficiently.

 

Most 02's sensors start to degrade after 65-70K miles. I'd recommend replacing the two sensors closest to the motor. All the dealers around here and Bosch recommend replacing 02's as they are what control your mpg for the most part for daily driving. Narrow band 02's, like in our trucks, have nothing to do with full throttle.

 

I don't know what to tell you. If I click on this: http://forum.gopowerhungry.com/ it takes me right to the PHP forum.

- Jack

 

At 70k, I'd change the plugs - and be aware of the sticking/breaking issues.

 

I went from a 91 canned tune to a 93 performance tune. I hate to say it, but it seems lacking in power compared to the canned tune. My mileage has dropped as well. The only thing keeping me from switching back is my AEM intake. The custom tune was written for my intake setup. You would think I would notice a power increase with a tune written for my AEM Brute force, but yet it seems lacking, and my mileage dropped.

I'm still waiting for a reply since September...

 

well, what type of plugs do you recommend? Stock replacements, copper, platinum iridiums, etc. Maybe I'll try giving that a shot I guess

 

Stay with the Motorcrafts. Longer life and the engine is happy with them, just follow the TSB and coat the shank with nickel anti-sieze and they should come out fine, next time.

 

You have limited choices: Motorcraft (preferred), Autolite, Brisk, Champion

Browse for detailed R&R info on here - there is TONS. and only ONE proper way to do it.

 

Another thing, one or two of the brands don't even make the plugs in the proper heat range.

 

ill stick with motorcrafts......just called the ford garage, $180 to change plugs sounds a little steep, plus the cost of plugs. Or is that normal.

 

If you have a 5.4 and they know what they are doing, that is reasonable. It usually runs about $350 including the plugs. Make sure they are following the TSB and have a high success rate on getting the plugs out.

 

I guess I should ask, are you aware of all the problems some have with changing plugs in a 5.4 3v? If not, you need to use the search feature and do some reading. It is not the big deal it used to be as a lot more is known now and there is a removal tool for the broken plugs.

 

uuhhh yah...I've read plenty on changing them. Normally I do all the maintence on my vehicles myself, but, that makes me nervious with all the horror stories and will pay a pro to do the work instead of potentially having a headache on my hands.

 

Some of the 'pros' have been breaking them. And then pulling heads. Not all are familiar, or defer to, the TSB.

Get it in writing, up front, on the $$$ labour for the job.

But you already knew that, right?

 

Lisle makes a pretty reasonably priced tool to fish out the shank or some have made their own tool from all thread, nuts and washers. There should be no reason that the head has to be removed but we still here of a dealer "selling" that from time to time.