I think I'm due for a tune-up. I have almost 90K on my '99 6-cyl 4.2L engine, and I last got it tuned up at about 30K at a Ford dealership. It's running a little rough and missing during acceleration at highway speed.

Based on what I recall from the sales ticket from my first tune-up, I don't believe the dealership put platinum plugs on the truck. Was this a mistake, or are plats optional?

 

The only thing plats do for you is get you more distance from the plug. That's why they can call them 100,000 mile plugs.

 

When I used to get my tune ups at Ford, they put in plat. plugs. Look in your manual. They should give you a parts number for plugs, etc.

I'd just stick with the stock Motorcraft plats., especially if you are not heavily mod.


If you're mod., then I'd go with either NGK irdiums or Denso (if your feeling rich).

PS--stay away from Bosch plugs! I have seen too many Ford owners waste their money just to replace the Bosch with Motorcraft/Autolite.

 

Use the exact plug recommended on the label under your hood (or its newer replacement, if applicable) unless you

1) Know exactly what you are doing (blower, nitrous, etc)

2) Don't care about how long they last or how well the plugs perform.

The recommended platinum plugs are a very good balance in performance and longetivity. Use of a non-plat plug may cause either short plug life or engine drivability concerns.

Personally, I have gotten excellent results from the Motorcraft and the Autolite double platinums.

I have read that Ford may be changing its plugs to a newer style plug, so your service provider if "Fine wire" plugs are now factory-recommended for your engine.

Steve

 

Maybe be careful. you might have a coil going bad or two like I just had on my 99 f150 with 50,000. #4 6 coils and plugs need replaced. If I wait too long I could burn up the catalatic converter at over 1k. Geeze, I want to buy American made but I never ever had problems with 2 Nissans I owned. When new, this truck needed new steering contol arm work. leaf spring bushings replaced along with the springs, and the passenger side head gasket had blown at 17,000 mi.

I don't race this truck, it's just a truck. I also had the shift gear lever repaired. I'm not too impressed but the ride is nice and the trucks inside molding is beginning to rattle already. To me, this is totally bs as 99 percent of all my driving is on city streets and hwys.

Now, with a 480.00 work order for my 2 coils and 2 plugs from a blue oval dealer??? I'm just not happy. Was going to use this money to help pay for other matters.

 

Yep, and why spend extra money on something that might get blown out of the aluminum head anyway... LOL

 

GWT,

With 90k, you're due for new plugs, even if they were changed at 30k, which I doubt. Put in the double platinum Motorcraft and fuhgeddaboutit. I saved money by buying at the Lincoln dealer across the street from the Ford dealer.

Yes, they're damn expensive (unless you compare them to bike plugs), but there is a lot of evidence that other brands may not work as well.

Also, and before you change plugs, run a can of SeaFoam through your engine. You may have a gunked up injector or two. And, consider changing your fuel filter.

Hope this helps!