Okay guys. Here's the deal. I decided to change the spark plugs in my '99 5.4l F-150. 93000 miles I thought was enough to put on the original plugs. Probably what was even worse is my LIMITED experience on engines in general. I got all of the plugs changed. (only took 6 hours one of which was spent going to pick up an extra extension) Problem is, now I crank up and the SES (service engine soon)light comes on. The truck shakes between 1000 and 2000 RPM.

The last time I had this problem, it turned out to be the #4 coil. Which makes me wonder, because while I had the coil off I noticed the plug wires on it were different from all the other ones.

Has anyone else had problems changing plugs on these trucks? I've seen all the posts about spitting plugs. Give me something new to work with. Help.

Jason

 

You must have gotten a connector on wrong or forgot one. double check your work...coil diff is no problem usually. You are running on 7 cly's most likely.


Welcome to the forums!!

 

Jason,
Welcome to FTE!
I've got to agree w/ the post above. Since you just reworked the plugs, that's the first place to look.
I'd guess either wires crossed or a broken wire or COP assembley.
Please let us know what you find.
Again, welcome to FTE.

 

Hey guys, what about this part>

"The last time I had this problem, it turned out to be the #4 coil. Which makes me wonder, because while I had the coil off I noticed the plug wires on it were different from all the other ones."

I'm going to start with checking the #4 again. I've talked to a few others and they said that it should be the same as the others. The damn thing doesn't look like it has an electrode at all. Just a spring with an insulator in the middle about half-way up. Any idea if it's supposed to be different??

 

The spring should touch the plug...

 

Did you buy the truck new? I have heard that aftermarket coils do look differently than the stock/oem. This shouldn't affect your performance unless that is the bad connection. As long as you're sure the plugs gapped and seated (meaning you can't torque them beyond what is required and they threaded in smoothly), then you should check that your springs and coils are sitting (make sure you use dielectric grease)semi-snug. Make sure your connections are on square and latched. I use dielectric grease there on the connectors as well. Prevents moisture from getting in.

My truck ran rough for 100 miles and I was ready to dive into the head again, but then it mellowed out. I didn't get a check engine light, though.

-Kerry

 

I bought the truck barely used. (14k) and had problems at 24k with the #4 coil then again at 50k. I figured it just had some kinks to work out.

The second time I had the coil replaced was when the Ford dealer changed the type of coil used. Still Motorcraft, but still different.

Call me arrogant, pigheaded, stupid... I went in to Ford today and had them hook it up to the idiot tester. It told them I was an idiot and that I hadn't seated the #8 completely on the plug. They hooked it back up for me and all was well again.

Guess I should have listened to you guys before I went and swallowed my pride.

The Service Dept Manager ran the diag himself and only charged me half price for it and then offered me a job when we found out that was all that was wrong with it.

Told him to keep the job, I value my sanity too much.

Thanks guys.

 

That's funny, must have some techs that always get it wrong? The price for good help these days.

Good Luck.

-Kerry