Service Engine Lite came on randomly, why?

[mrazndead]

Something weird happend when i was driving on the freeway this morning. I was cruising at 65mph, and when i was going uphill I stepped on it a bit more to give it more ummphhh... and was going at 72-75 uphill. I noticed the car stuttered a little. then when i cruised back down to 60-65 going downhill the serviec engine lite came on for the first time, and blinked for about 10 seconds. then it went away. hasn't came on again since driving in the city. i wonder is this normal? has it happend to yall?

Should I get a powerchip or edge tuner to really open up this bad boy??! at 66-70mph the powerband kinda sucks.....

 

[FordandPolaris]

I can almost guarantee it had a misfire, and therefore one of the cylinders is not firing under load. Best bet is to stop at a local parts store. Most of them have a scanner that can tell you what the light came on for, and if I am right, which cylinder is misfiring. If you don't know how the scanner works, the workers there will help you. From there, I would replace the Coil on Plug, as well as the plug itself. Should fix the problem, and improve the powerband issue. Freeway speed is often when these issues are first exposed. Depending on how confident you are, you can replace these yourself fairly easily, otherwise a shop can do it for a few hundred bucks. If you need any more info on how to replace the plugs, let me know and I can give you a write-up. I have done this several times myself.

However, if no misfire codes are found, and instead there is a different code, post it back up here, and we should be able to help you from there.

 

[mrazndead]

Thank you it does feel like a misfire now that I think of it, should I change the coil at the same time as the spark plugs or just change the spark plugs first?

Can you give me a brief right up?

Thank you.

 

[Jeff532003]

Search YouTube for a how to video. There's a ton of them for the 5.4 because its also in the f150. You don't have the two part plugs in yours so if you see those videos about the nightmare it is dont worry. If it where me I'd do all coils and plugs. They're going to start to go bad with the age of your truck. They're around 40 bucks a piece so it's not a cheap job but it is good insurance against a break down.
I'd probably do what fordandpolaris recommend first though and go get the codes read. The auto parts store can tell you why it turned on.

 

[FordandPolaris]

Well if anything is bad, its most likely the coil. But you will have it out and apart anyways so may as well spend the extra 5 bucks and do the plug. In other words I would do them both.

Basically the COP's and plugs are located underneath the silver fuel rail. They have circular tops, and are black. They look like this...

https://www.google.com/search?hl=en..._coil_2wire%2Fcop_coil_overview_2.php;261;291

There is a plug that gives the COP power, unplug that. Next there is one small bolt that just holds it down, take that out. Can't remember the exact size, but it is not in very tight. After that, the COP just slides out. Down in the hole is the plug. This is the tricky part, you need a spark plug socket (5 bucks at any auto parts store) and some extensions. Depending which cylinder it is dictates how many extensions. You will also want atleast one universal joint (2 depending once again on the cylinder in question). Push the plug socket down into the hole and push it onto the plug, there is a little rubber piece that is supposed to grab the top of the plug. It shouldn't take much torque to loosen it up, and then it should just pull out. Try and clean out the hole as best you can before doing this as you do not want too much debris to fall into the cylinder. I use some compressed air to do this. Put the new plug in the same way.

MAKE SURE IT DOES NOT CROSS THREAD!!

These heads are aluminum and therefore the threads are easy to mess up. When I have done them, I tighten them down fairly snug, but not as hard as I can. There is a certain torque spec out there that I am sure someone will post up, but I do not know off hand what it is and haven't used it anyways. New COP goes back in (should slide right onto the plug, you will see what I mean when you do it), and then just the small bolt and plug and she'll run (almost) like new.


When you get the codes, if it is one of the front cylinders (1, 2, 7, or 8) I would do it yourself. The rear ones are a lot more tricky as you cannot really see what is going on, and need to be creative with extensions and u-joints, etc. That will be left up to how confident you feel.

 

[mrazndead]

OK thanks guys. I just ordered an 8 pack set of coils and sparkplugs.

Will change out with my uncle who's a mechanic next week,

Thanks again.

 

[Jeff532003]

Have fun with this rear ones. It's a blast like was mentioned. The hardest part is getting the coils off of them IMO. Be sure to have two universal joints also. The ball joint style work best but the knuckle ones will get the job done.

Oh and while your doing all this if your egr valve is old this is a great time to replace it and take the throttle body spacer off to clean the carbon out of the ports. Do both and you'll think your truck is new.

 

[mrazndead]

I'm tempted to change those too. Maybe I will just clean them for now. Going broke with the car. Did quite a bit and ordered a bunch of stuff this weekend, will take pictures of all the new accessories next week.

 

[mrazndead]

got the stanton lock gas cap today. fits works great - we'll see how long it lasts.

got some cambuckle cables, pretty good quality

got a hitch cargo carrier, kinda disappointed with some of the spot welds and also one hole isn't aligned for the bolt. but it looks pretty decent for the price.

all courtesy of amazon.

got some more goodies in tomorrow.

 

[mrazndead]

Update:

Spent a few hours this morning but got new motor craft plugs and coils in!!!!

Runs like a champ now. No more power band issues or hesitation. Smooth like butter.

Found out the previous owner put new plugs in but didn't gap them!!!! They were at .20 when we pulled them out hence the cel at high loads. Runs like a completely different SUV. Awesomeness with new proper plugs and coils. Gapped at .054