Misfire cylinder 7

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timberwoof

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Had my check engine blinking on me a couple weeks ago and took it to autozone to get it read. Came out as misfire in cylinder 7. The guy said it may be the coil is bad. At the time I was thinking basically the same thing but it never happened again until a few minutes ago. What are your opinions on the matter?
 

Big Red Monster

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how old is ur truck and have u ever had a tune up? right now mines at the shop, needs new spark plugs and prolly a coil or 2. this seems to be a common problem, only problem is mine wont throw the damn cel, which makes it harder for the mechanic to figure out whats wrong.
 

Big Red Monster

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ohh 3 valve motor, i have heard alot about the plugs breaking off in the heads on those. i would just change the coil, my dad had the same problem with his 97. changeing the coil fixed the problem
 

wiley84

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i had the same thing happen to my 07. you need to do a tune up on it. change the spark plugs and the coil on #7. I would recommend doing this soon before you have more problems. Over christmas we had this problem when we were traveling. wound up at two different dealerships and had three coils changed and the sprak plugs. before you get into the problems that i ran into i would do a tune up. the spark plugs can break really easy on these, the dealers use a cleaner that breaks up the carbon the on the plugs so they dont break.
 

Dib52

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I had similar issues on my 08 but no CEL. We had to run a power balance through the OBD port to determine that cylinders 2 and 5 were the issue. Changed the coil packs on those two cylinders and problem solved. Having the info that cyl 7 is the problem, just swap it out with a new coil, about 45 bucks. With 85k on the ticker, might want to think about a full plug change, but they can be a real PITA if they decide to break like most do.
 
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timberwoof

timberwoof

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I've been watching several different YouTube videos on how to change out the plugs on these monstrosity of motors. Looks like its gonna take more time and patience than I'm use to having when it comes to doing tune ups. But.... It has to be done none the less. I'm just gonna have to grit my teeth and take it with a little lube.
 

Mikiedoo

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Yeah, coils can go bad like that. It will fire ok sometime, then all of a sudden start missing, then go right back to firing fine for a short period. Definitely get it and the plugs changed.
 

jdan

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Usually when ever I pull out a misfiring coil the boot has condensation on it.
I've dried them off and put them pack with success of saving a few bucks.
But it's like 50/50 on fixing the issue.
 

megan4221977

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Hi! I have an 11 expedition with cylinder #7 misfire… this is after having random misfire… changed all plugs, just got truck and looked original… then #7 came up, changed all coil packs, rather be safe then sorry… still missing, changed out fuel injectors and it’s still #7 misfire… 205k miles, not losing any fluid, engine is quiet no loud ticking or anything but if you get up on it it bucks and shimmers! Been researching and got connections to check compression, neither one fit(04 or newer Ford 5.4l)… could it be rocker follower? Seen some videos on that and camshaft phasers, but again no noise, seems to run good after warm up, until you get on it!
 

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