Coil on plug Ignition problems

FordGT2K

New Member
Sep 18, 2003
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South Coast, MA
I have a 2000 GT Convertable, the list of bolt on's inculde a BBK cold air kit, and a Mac catback exhaust.

I have had a repeated studder and a loss of power the first time the dealership discovered a problem with the one of the coil on plug ignitions being faulty. The studder went a way after the replacement of the ignition module, I later had another one die in a similar manner.

My question to anyone available, is this a common accurance, and am I going to need to keep replacing these for the entire life of the vehicle? Or is this a cycle through the eight to possibly get rid of a bad set.

Also is there any sort of maintance that any one suggests to keep these things for dieing on me?
 
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I have priced them, from the dealership they are $102.22 and online i found them for 36.95. The only problem that i am now having is the dealerships want to sell me the coil for the for the cobra and not the one for the gt. Saying that it is the motorcraft part that is speced for my car. Which when i look at motocraft's web sight it gives me a different part #.

The way that i have used to identify it is when the car is idling i unplug each pack indiviualy and listen to the motor for any change. It for some reason seems to work better than computers right now.

Yes i am getting a code now. I wasn't getting a code 2 months ago when is started but i could feel something comming and didn't want to wait for it to let go, but the computers couldn't find it going bad. 3 differnt compters and techs. not a cheap problem to find and turning out to be a bigger pain in the butt.

Is the stock 4.6 v8, not the cobra, a 16 valve engine???

kirkyg said:
I've never heard of them going bad :confused:

Have you priced out how expensive they are? And do you have a way to identify which coil pack is gone? I guess your getting a code?

kirkyg
 
Yes your looking for the coil packs for a SOHC 4.6L v8. NOT a cobra DOHC. I'm not sure what kinda BS the dealership is feeding you but my guess is that they are most likely the same part and trying to get you to pay them instead of buying it online. Has anyone else had any experience with replacing their coil packs?

Is it safe...btw to just pull them off while the car is running?

kirkyg
 
The SOHC and the DOHC coil packs are ever so slightly different. Motocraft does have two differnt part numbers for the two vehicles. But what I have found out is that the dealerships really can't answer the questions when you ask them. :shrug: Is all I really get so it was bacilly a whole day spent learning everything that I could about the coil on plug system.

I also apologize for my miss typing ealier, I don't actually remove the coil from the plug I just unplug it from the system. All the techs that I have worked with up until know have done just the same to see if they can pin point the misfire that way.

If you are interested in learning any more about the coil on plug design check out this web page (http://www.asashop.org/autoinc/feb2003/mech.cfm) I found it very informative about the whole system. Including the fact that when a coil misfries or registers as dead in the control module the module sends info to the computer to shut fuel off to that injector.

Please if anyone else has any other input or experiance with this, all input good or bad is welcome.

Thanks for the help.

oh yea and if anyone is looking for their coils
Motorcraft part number DG-491 is for the 16 Valve SOHC
and part number DG-492 is for the 32 Valve DOHC.


kirkyg said:
Yes your looking for the coil packs for a SOHC 4.6L v8. NOT a cobra DOHC. I'm not sure what kinda BS the dealership is feeding you but my guess is that they are most likely the same part and trying to get you to pay them instead of buying it online. Has anyone else had any experience with replacing their coil packs?

Is it safe...btw to just pull them off while the car is running?

kirkyg
 
A COP going bad is pretty common, we replace them pretty often at my dealership. Majority of the time its just a boot problem, which you can get seperately instead of buying a brand new COP assy. I have rarely seen a bad coil pack.
 
Hey 5.0's 5 ever

Thanks for that tip. I read something about that last night and didn't know if that was actually an option. Is there anything that i can do to keep the boots from going bad??? I read they the coil will actually arc out through that boot and because it is inside the head it is too hard to really see. Do you recommend putting anything on them to preserve the rubber???

Thanks

5.0's 4 ever said:
A COP going bad is pretty common, we replace them pretty often at my dealership. Majority of the time its just a boot problem, which you can get seperately instead of buying a brand new COP assy. I have rarely seen a bad coil pack.
 
I have the same problem that you are encountering.. and I am ready to sell the damn car over it..

Mine started more because I was changing my plugs every month due to my nitrous system, always trying a colder plug, then re-gapping them, then checking to make sure i didn't get lean conditions.. its really easy to change the plugs, but anyone that has changed them knows that it's very easy to strip the bolts while doing em, and then they never get tight, and wiggle around sometimes..

I'm currently getting a "stumbling" at idle, and also downlow in the rpm's range... it feels strong when at WOT but I really can tell my car is noticable slower.. I have replaced a few of these bolts with Drywall Screws and they seem to stay put, but I think that one of the COPS have gone bad... I just want my car to run smooth again, and fire on 8 cylinders!!

also, alot of my conclusions are based on theory, since I have no codes, lights or anything!!! I'm just trying things like unplugging the coils or just tightning them down and seeing the motor respond
 
My car developed a slight miss when it was fairly new so the dealer replaced two coil packs and it's been fine since then .... that's the only time I've been back to the dealer since I bought my car. When I installed new sparkplugs I used anti-seize on the threads of the plugs and also gave the rubber boots a healthy coating of dielectric grease on the inside ... that will make future removal much easier.
 
01'TRUE BLUE GT said:
My car developed a slight miss when it was fairly new so the dealer replaced two coil packs and it's been fine since then .... that's the only time I've been back to the dealer since I bought my car. When I installed new sparkplugs I used anti-seize on the threads of the plugs and also gave the rubber boots a healthy coating of dielectric grease on the inside ... that will make future removal much easier.

I would love to bring my car to the dealership, but in my town they will go over it with a fine tooth comb and see a Chip.. or a timing adjuster, or for that matter a plenum and come up with some bullcrap saying that any of these components caused a Coil Pack to go bad and they will void everything.. They could be in the wrong, but at the end I will be the looser of the argument, the guy sitting outside the dealership wondering how he got himself a bill for $500 bucks of labor and a voided warranty!!!
 
That could also be an o2 sensor going bad. If you do not get a check engine light soon it most likely is not though. I still haven't heard of any problems with the COPS in the past thats probably why your not getting alot of response here.

kirkyg
 
FordGT2K said:
Is there anything that i can do to keep the boots from going bad???

There really isn't going to be a certain thing that will keep them from going bad. The heat and age just causes degridation of the boot. Fluid getting on them also causes problems for the boots. With the 4v motors that have leaking valve cover o-ring gaskets the oil will do serious damage to a boot. They swell up and majority of the time just rip apart leaving half of the boot still down in the cylinder head when you pull them out.
 
Have you ever heard of Micro tech's coil on cap tune up kit. (http://www.hongsui.com/625337.html) Would that solve the problem of the boots when I get a coil acting up. Thanks for all you input it has been most helpful in getting this stuff fixed. :nice:


5.0's 4 ever said:
There really isn't going to be a certain thing that will keep them from going bad. The heat and age just causes degridation of the boot. Fluid getting on them also causes problems for the boots. With the 4v motors that have leaking valve cover o-ring gaskets the oil will do serious damage to a boot. They swell up and majority of the time just rip apart leaving half of the boot still down in the cylinder head when you pull them out.
 
There is supposed to be a TSB for an RF interference problem on some Ford cars with COPs, but I can not find anybody that has the TSB.

Anybody here have it?

I too have that idle problem on my 03. Maybe it is an 03 thing? What is your PCM code (sticker on the computer itself)? Might be worth figuring out if there was a bad batch of COPs, or oxygen sonsors, or PCMs, or whatever.

I can relate to your frustration. Three mechanics have said that I have random misses, but every one of them is stumped as to what is causing it. None of them were willing to try any new parts. They want to see the "big and obvious" diagnoses or you are out. It sucks.

Let me know if you find a good place with reasonably priced COPs.
 
I have 2 placed online that sell them for about $60 each.
www.rockauto.com & www.fordpartstore.com

Both are about half the price of the dealership. Aslo look at the link that I posted above! It seems as though from what i have been able to find out from a few days of reasearch, is that the boot will arch out like an old set of plug wires. If you go to that page you will find a company that is selling boots and springs for all 8 coils for the price of a single coil from the web.

I do know that ther is a TSB for an ignition misfire and the TSB # is 03-14-04 but I have not been able to find anything written on it beyond that. Please let me know if anyone has it or knows where I can get the full written document.

Do you know which COP is acting up?


Red Dragon said:
There is supposed to be a TSB for an RF interference problem on some Ford cars with COPs, but I can not find anybody that has the TSB.

Anybody here have it?

I too have that idle problem on my 03. Maybe it is an 03 thing? What is your PCM code (sticker on the computer itself)? Might be worth figuring out if there was a bad batch of COPs, or oxygen sonsors, or PCMs, or whatever.

I can relate to your frustration. Three mechanics have said that I have random misses, but every one of them is stumped as to what is causing it. None of them were willing to try any new parts. They want to see the "big and obvious" diagnoses or you are out. It sucks.

Let me know if you find a good place with reasonably priced COPs.
 
No, I have not identified the bad cop/cops. The mechanic said the misses were random and not just on one cylinder. That is why it is hard to pinpoint. Because of the randomness, it might even be something else.

It sure would be great to be able to read that tsb before I spend a bunch of money on COPs. Because my car is still fairly new (8,000 miles I believe), I dont' think I would start with the boots.

There has to be a Ford employee around here someplace that can get us the TSB. ANYBODY? :shrug:
 
I just followed the links above. The Fordpartsore link returned coils for a V6 and had no place for me to specify a GT (maybe I browsed too fast to see it). The other link (Rockauto) took me straight to the correct coil. It even showed the 32 valve coils. Just thought I should mention this just in-case somebody else browsed the Fordpartstore and came up with the incorrect part as well.