I am still having a problem with what seems to be a misfire during a small load 1200-1800rpms, enough to shake the whole truck. Idle is fine, in drive with foot on brake you can feel the engine stumble from time to time.

Tried fuel injector cleaner, and new plugs, nothing. Found and fixed a unrelated vacuum issue that helped performance a lot. But not the stumble under load.

Took it to the local Ford Dealer this morning. They said that the COP on 6 and 10 were bad and "had cracks" on them, and that one of the spark plugs is bad and has a crack.

I know that when I put the plugs in I was gentle, no excessive torque or sideways angling. I didn't crack it on install. Also the 10 old plugs I replaced were pristine, clean and nice thanks to the COP sealing the holes. No cracks on any of the old ones.

1. Can a bad COP "crack" a spark plug?
2. Can I call out the dealership on their lie?

I am guessing that their mechanic cracked it during the diagnostics.

 

If the COP boots are bad it can lead to what is called "carbon tracking" down the ceramic. To the naked eye, they can look like little black cracks in the ceramic. Basiclly the spark will travel down the outside of the plug instead of the inside.

 

I just love the logic used here.

I had a misfire.

I replaced the spark plugs.

The dealership tells me one of the spark plugs is cracked.

The lying dealer cracked my spark plug!

Can I call out the dealer on the lie? Absolutely, but how will they be able to fix your truck when they're all rolling on the floor laughing?


I can only imagine what your parents taught you about personal responsibility.

 

Guys, I've been a G(bailout)M guy for 27 years, Im trying to change that, that why Im here, but theres somecry baby so and so's here like I've never seen before. The dealer cracked my plugs, the body shop guy that didn't charge me a deductable, wrinkled my headliner, on my 9 year old truck,that I knew was bad and I threatened to turn him in to the BBB.

Ever wonder why our country is in the shape its in. Lawyer up boys your gonna need it.

 

Are you two females done bitching? How about helping this guy fix his truck or are you going to fillabuster about morals in the US? Gees. Anyway, were there any codes on the scanner that came up? If not since they are replacing the plugs anyway what difference does it make if they broke them? Just ask for your parts back and if they are BS'ing you call the BBB. I would check every hose, and wire on the engine and see if any cracks/fraying are visible. Either that or there is another vacuum leak somewhere else. Hows the fuel filter, air filter etc?

 

Seeing as you are writing about me in half of this post, maybe you should go back and READ and INTERPRET the English language before you post erroneous claims as to what someone stated. Or maybe just go back to GM...

 

To the OP, have the dealership show you the bad COP boots and the cracked plug. How long ago did you change the plugs? At the most have one plug replaced and get some new coils.

 

Didn't expect to incite such a response....typically I dont feed the trolls but I have to post a response to explain.

The dealership I took the truck to has a bad reputation already(google and angies list), They were merely the closest shop around with the correct gear to diagnose the problem.

They quoted me $230 to change the spark plugs, for grins I asked how long it would take and he said "About 30 minutes, we can usually do it in less than a hour in and out.". I said "Are you sure?" He said "Yes", I then brought up that the heads were aluminum and that the spark plugs are steel, and that your not supposed to change the plugs while the engine is hot or they will strip all the threads. He seemed confused at this point how a customer would know what heads are, let alone what they are made of. I changed the plugs myself.

I am not a ASE certified anything, I installed the plugs by taking my time and being careful. It's not the technician's fault that he is placed in a high speed, volume focused environment where he has to fix 10 cars an hour. I don't know and can't actually prove how the plug got cracked, in fact I suspect that Archion is correct and it wasn't, a carbon trace would explain it.

That is why when they say the plug cracked due to do or over, or under, voltage I am suspect, porcelain is not going to crack no matter what voltage you apply to it.

I didn't threaten to sue or report anyone, over a $3 spark plug? Really? What I wanted to find out is if they are trustworthy, and knowledgeable, which I can only assume at this point is no. If I ever need to get something else done from a dealer I'll drive or drag the truck the extra 20 miles.

They charged $175 for the diagnoses. I declined their offer of $491 for 2 coils and $1488 for all 10.

 

I looked at all the Coils very closely when I changed the plugs, all the coils were cleaned and they looked physically fine. This problem is months old and I changed the plugs early June.

Going to replace all 10 coils with aftermarket from eBay for $154 and see where that gets me. Plug is already done.

 

No codes, me, and a ASE certified guy went over the engine pretty good and found the first vacuum leak, everything else looks clean and perfect. Air filter is a new K&N, haven't looked at fuel filter yet. But with direct injection I think i would be having more problems than 1 or 2 faulty cylinders if the filter was clogged.

 

$175 for diagnosis!? I thought the $90 charged around here was robbery! I would have declined a repair bill for over a thousand dollars.

What do the COP boots cost anyway? Contact user partsguyEd and he will quote a good price. Minimum to save money, just buy 2 boots and pay for the others when you have more money down the road.

I had a shop quote me over $500 just to do the 8 spark plugs in the 5.4 SD I had before my current truck. That was laughable. They were going to charge me $20 per plug, and $40 labor for each. HAHAHAHAHAHA!! No way.

 

How many miles on the truck? Maybe a bad injector or two? Try the new boots and keep us updated if that solves the problem.

 

Well if the filter is dirty or of low quality it could have let debris pass by and clog an injector. That is what I was eluding to as jc8825 suggested with the clogged injector.

 

I am the one who had the dealer dropping filter clamp inside my turbo intake and than denying the responsibility, so I am definitely no friend of dealers, but logically how the technician could crack the plug?
I quit driving vehicles with spark plugs years ago, but still have them in bunch of small engines in power washer, dirt bike, PWC and so on. The spark plugs can just fail with no warning and for no good reason. That is how they work.

 

hmmm aftermarket air filter(oiled cotton media) oil contamination on MAF?