How did your dealer test the spark plugs? Did they take them out and look at them or just assume that because they're under the recommended mileage that they were ok? How about the coils? Were they tested or just assumed by the dealer to be working fine?

 

You might want to do your plugs anyway. In my pic, the plug on the left was taken out at exactly 75,386 miles with normal driving (never towed anything, I dont drive hard at all) on my 2005 Lariat. You have 116,000 miles. Notice the tip of the electrode compared to the brand new one. I can only imagine what your's must look like. Not saying this will definitely resolve your issue, but it is definitely worth a shot.

 

Is everyone using OEM plugs or is there another majority preferred aftermarket plug? Also, how do you check the coils?

I'm not sure how my dealer checked them, but I believe I'm going to pull them out and replace them in the near future since they are fairly cheap to replace.

 

Does your truck have a 3V engine? If so, you WILL use every curse word that you've come to know in your life, if you do this yourself. If you have the dealership do it, you WILL use every curse word that you've come to know in your life, on top of wanting to burn the place down.

 

The factory recommended plug change interval WAS 100k, but on the 3V engines Ford has revised this to 60k. Any dealer who tells you that your plugs are fine at 116k is incompetent. They just don't want to go through the hassle of changing them - and it IS a MAJOR hassle.

Granted, the tranny service recommendation under "normal" service is 150k, but under severe service it's 30k. Either way, running factory tranny fluid to 116k is just stupid. Not very many people fall under the definition of "normal" service 100%.

I know tarajerame can be very abrasive, but the man DOES KNOW what he's talking about.

I could care less what you think about me, but I'm going to call a spade a spade - if you don't bother to do common sense preventive maintenance on your vehicle, you deserve to have issues like this. Have a nice day.

 

Well, I'm still debating on doing the spark plug swap out myself or paying someone. I had my mind made up to do it on my own until I called the local mechanic my family's business uses for all their service vans. He only wants $227.33 for labor or $296.17 for labor and parts. Both prices include tax. That's a heck of a deal compared to what most of y'all have said you paid someone to do it.

 

One of the issues I ran into recently was a bad Thottle Positioning Sensor. I had believed it to be the transmission until it went into safety mode while I was driving. If you haven't heard of "safety mode", it is anything but safe. The truck will completely shut-off on you while driving because the TPS gets stuck open or closed, error code says either. My dealer said these sensors go bad quite often and he kept new ones on stock at all times. 20 minutes and 20 dollars later and my truck run like a dream again.

 

Ask him how much extra he charges to extract broken plugs, that's what can add up fast. Make sure he uses the improved Motorcraft plugs - SP-507 single platinum or SP-515 double platinum. If he wants to put a different brand in, try to discourage him, results have been quite mixed. Autolites are a no-no, some people are having good luck with the one piece Champions and E3's, others are not. Brisk makes a 1 piece plug, but it's not platinum and it only lasts about 25k. There are no other brands made.

If you decide to tackle it yourself, make sure you have the right tools (it's not a standard size plug, it's 9/16), follow the TSB (carb cleaner, nickel anti-seize), and have a Lisle extraction tool available. I'm betting at 116k they are gonna be seriously carboned and will come out real hard - you could easily break all 8.