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Discussion Starter #1
My 2006 GT just hit 70k miles so I decided it would be a good time for a tune up... I did my research here about the plugs breaking and whatnot before attempting to change them. Well even after going slow and using the PB Blaster (2 hour soak), 4 out of the 8 broke. Batting .500 :heha: But I bought the tool and got those out with no problem. I THOUGHT that would be the hard part... but it was after installing the new plugs that now I'm having problems.

I bought the OEM Motorcraft Plugs off AM... whole set for $69... They have nothing but 5 star reviews on there. So after applying anti-seize and torquing to spec... I fire it up, and blah... Sounds like I have a performance CAM in there, idling terrible and when you give it gas it doesn't want to go.... Eventually I got random misfire codes... but they changed cylinders every time.

Now here's where it gets tricky... I've seen 2 different gap sizes for the 05-07 GTs. Some people say it's .045, others say it's .054. I checked with O'Reilly's and their computer said .052-.058 and .054 are what these Motorcraft ones come pre-gapped at (can't change the gap either). I measured them and they were all around .054. I called AM customer service (best out of any site) and he is sending new plugs to try, in case some are faulty somehow?

So for now I did some trial and error, I cleaned off the old stock ones (4 remaining after breaking other ones) and stuck them in with some of the new ones. I fired it up... and It sounded about 80% better with only slight hesitation. So there lies my question... WTF is going on?! Are the new plugs gapped too big, or I've read on F150 forums that maybe my coils/boots could need to be changed because the new plugs require all the spark and if there's any lack of flow in the coil it'll cause misfires. I'm lost and need some help asap! Been without my car for a week now, driving some 1987 Buick Regal as my back up... I need my speed back!!! Any insight would be greatly appreciated! Thanks!
 

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Were the new ones the Fine Wire Single Platinum, or the Copper Core?

You could have got a set of the Fine Wire from Advanced Auto for 40 bucks plus tax
 

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Discussion Starter #3
Were the new ones the Fine Wire Single Platinum, or the Copper Core?

You could have got a set of the Fine Wire from Advanced Auto for 40 bucks plus tax

According to American Muscle's description they're Copper Core... But how does that cause my problem?
 

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I recently changed mine on my 06 and some of the things I had read while researching was the following.

Some people over do the anti seize and it gets hot and causes misfires and codes. There were also some that had gotten anti seize onto the tips which caused the same.

I was also told to be very very careful to put the COP's back on the same cylinder they came from.

Make sure the plugs are torqued properly and all of the wiring harnesses are on tight.

I know this is basic stuff but it's usually the thing I pay least attention to. Maybe it will help maybe not.
Good luck
 

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Discussion Starter #6
I recently changed mine on my 06 and some of the things I had read while researching was the following.

Some people over do the anti seize and it gets hot and causes misfires and codes. There were also some that had gotten anti seize onto the tips which caused the same.

I was also told to be very very careful to put the COP's back on the same cylinder they came from.

Make sure the plugs are torqued properly and all of the wiring harnesses are on tight.

I know this is basic stuff but it's usually the thing I pay least attention to. Maybe it will help maybe not.
Good luck
Actually I was wondering if maybe the anti seize could have done something... I had help from my brother in law and he piled it on the first one, told him to go easy, so then he wiped some off, but he may have gotten some on the tip which i told him to be careful not to. Should we let it dry a bit before putting them in too? We made sure to put all the COP's back where they came. I double checked the wiring to make sure it was all connected tightly. We tightened to 29 ft lb, like it said on the plug boxes. When the new set comes in, i'm going to make sure and go easy on the anti-seize and use some contact cleaner on the electrical plugs just in case.

Thanks for your idea! Just curious, which plugs did you go with? and what were yours gapped at?
 

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I install the motorcraft all the time with no issues at the preset gap. Without being there I would say make sure they ate not over loaded with anti seize. And clean connection between the coil and plug. Make sure no pins back out of the coil connector. And injectors are hooked up. Also it says u torque them. Make sure that they are tight. I seen in some Cases were they are under torqued. Cause some
Loss of compression.


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when i was n/a i ran champion 7989 1 piece plugs that i gapped to 45, no problems after 30,000+ miles, i have them in my garage if you want them cheap, i know they work perfect. hit me up with a pm if your interested :bigthumbsup
 

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Thanks for your idea! Just curious, which plugs did you go with? and what were yours gapped at?[/quote]


I went with the Autolite HT1 and they were pre gapped.
 

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Discussion Starter #10
Well I bought one Autolite HT1 today at Advanced to put in the cylinder that was still giving a misfire code. So that's 4 stock original plugs, 3 Motorcrafts and one Autolite currently installed... Fired it up, and she's purring like a kitten.... So I'm wondering if a couple of the Motorcrafts I received were bad? When I get the new set Monday I'm going to take everything out... clean everything really well, and install the new 8 ones without any anti-seize or anything and see how it runs. If those don't work... I'm heading to Menards to grab the other 7 Autolites. Thanks for all your help! :worship On a good note, we got the lowering springs and new shocks put in over the weekend! :laughlitt
 

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So the problem is fixed! We took all the plugs out and replaced them all with the ones AM sent Monday free of charge. Upon further investigation I noticed he did use quite a bit of anti seize, but those were the ones firing fine. After we separated the good and bad we had 4 good and 4 bad so it must've been a faulty set. Now she feels like a brand new car. I had also had a recent drop in gas mileage... I even changed the fuel filter to try and fix it but it didn't do much. But now that problem was also solved. My mpgs jumped back up dramatically with the new plugs. I'm going to start changing them every 20k miles from now on! Lol thanks again for all your insight guys!
 

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Old thread revival

I just picked up a 3v Gt that needed a motor. The motor gave the Original owner massive trouble after a plug change. Cherry red cats, knocking, backfiring, stalling etc.. I got the car home and pulled codes and assessed the damage. I noted originally no oil burning, and on occasion the motor smoothed out and good oil pressure and no noise from the motor. Being that the original complaint stemmed from the plug change and having dealt with my 01 2v PI and 04 Marauder, I pulled all of the coils and plugs. I noted cyls 5 and 7 were fouled.

I installed 8 new auto lite HT1's and proceeded to clean the boots noting some anti seize on the base of the boots. Some brake cleaner and a fresh rag, I cleaned all 8 coil boots, checked springs for corrosion and contact and then after I felt they were sterile enough I recoated them with silicone spray and put some dielectric grease on the springs. I reinstalled the plugs with the threads lightly coated in anti seize making sure only the threads had the compound on them. Making sure no anti seize was anywhere near the boots upon coil installation.

I started the car and all was well again in the world.

If you are having problems after a plug change, remove everything and clean the coil boots inside and out, spark plug wells etc. if the problem continues, suspect the offending new plug is bad. This car had brandy new auto lites and two were suspect.

These cars need a very neat and clean plug install, any contaminants such as stray antisieze will cause arcing And poor drivability. Brake cleaner will remove carbon and other conductive materials without harming rubber. Silicone spray will soften and replenish elasticity to the boots and make them water proof. Dielectric grease will keep the spring from oxidizing and allow for easy boot removal in the future.

I hope this helps someone in the future. Sometimes the answer is simpler than you think. This car went to two mechanics who said the motor was bad, by backtracking, I fixed this car In 45 minutes and spent 90 bucks. The motor runs smooth as silk and today I'm headed over to the dmv to put it on the road.
 
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