P0307 #7 misfire

[megan4221977]

Hey… ok #7 misfire… I bought truck 201k on it, ran smooth no noises, was told it was maintained… well noticed when driving on interstate, when stomping on gas to get up and go it would buck and engine light would flash… changed filter and fluid in transmission, seemed ok… did it again, happened to have computer tester and plugged in while driving and read random misfire, so changed all the spark plugs… #7 misfire, so changed all the coils packs, #7 misfire, changed fuel injectors… you got it #7 misfire still!!! Just took off the valve cover as was told could be rocker follower, they seem good very tiny to no wiggle at all!! Even checked spark at #7 and was good… know I’m stumped!! Not losing any fluid. (Coolant or oil) only this code shows, clear it runs great till you have to give a little gas to maintain speed up hill or something… then struggles, jerks, sputters, etc… check engine light flashes… clear code while driving (3xs in a row) and drives fine again. Also the spark plugs looked original!! Replaced with OEM… even did the dioeletric grease stuff on coils… any ideas/help… no engine noise, runs quiet since I got it.

 

[Goofy173]

Since no answers yet, I will just throw out it possibly being the injector harness. Also check compression.

Really seems time to think out of the box.

One thing also sticks in the back of my mind is very, very unlikely, coil 7 bad again? What would be the coincidence? I've had a brand new coil be bad just last year, but that you replaced all, and a bad one just happens to be #7 again? Not likely.

If it were mine at this point, I have a really great mechanic I would have look at it. Mine takes 2 weeks to get into but he's always found my head-scratchers. Maybe you have one of those?Mines only $75/hr where most are $90 here. Not that much considering how much time and money you've already spent.

Good luck. You need it with this.

 

[megan4221977]

Yeah I was doing compression test today! Been researching everything!! Someone said to noid light the injector. Friend is a mechanic.

 

[Motorcity muscle]

Tough one, might be easier if more cylinders were throwing codes. Have you checked the fuel pressure, filter?

 

[megan4221977]

I actually had to change out the fuel pump like 5 months ago! So everything is new there… it didn’t start till after I did spark plug change… waiting to do compression test as none of the fittings fit… had to order special one for ford!

 

[Trainmaster]

You can try switching injectors between cylinders and see if the miss follows, but I believe your problem is with ignition. Triple check your ignition system. Look carefully at the connector to the coil and the leads, as a compression problem would have to be a bad one to show as a miss with a flashing engine light. That signifies the failure of the firing of the plug or breakdown of the spark.

 

[megan4221977]

Ok will switch around, cause after new coils I plugged in spark tester and was good flashing bright and quickly!!! Spark plug shows sign of firing! You know the tiny bit of discolor and little bit of soot looking… but still new… lol

 

[Dennis_H]

When I replaced plugs etc. I started getting an issue. Went through the coils, etc also. Turned out to be a new plug that was bad. Didn't fire all the time for some reason, but replacing that one again fixed the rough running.

 

[megan4221977]

I pray it’s that simple! I really don’t want to do head gasket and timing!!

 

[Trainmaster]

Switch the plug and coil to a different cylinder... and see what happens.

 

[megan4221977]

Well did compression test.. checked #5-7 cylinders, 8 is hard for my short self to get to… all were the same 150psi… so that’s a good thing! Waiting on gaskets for valve covers now, none in stock around me so had to order

 

[Frank Swygert]

I'd switch too. Could first, and if the misfire doesn't follow the coil I'd just get a new plug. They aren't costly but hard enough to get to that I wouldn't want to change two. Hope they are all easier to get to than on my 2005!

 

[megan4221977]

Yeah I forgot to put mine 2011 Ford Expedition 5.4l 3v… has 20inch rims and I’m short!! I have a step ladder!! lol waiting on valve cover gaskets to put back together, before starting back up

 

[Dustin Gebhardt]

As Trainmaster said, you may want to check the connector for the COP. The rubber o-rings on mine were falling apart, which prevented them from making a good connection to the COP. I replaced all 8 of mine and haven't had an issue since then with misfires.

You moved the COPs around and the issue stayed with #7. You changed the plugs and the issue stayed with #7. It doesn't appear to be related to the plugs nor COPs themselves. That leaves the cylinder, but the compression test came back good. A broken roller follower could cause this misfire, but you said that it looks fine, too. So that eliminates most of the mechanical items. I'd check the COP connector next. Here are the ones that I bought:

ignition pigtails

 

[megan4221977]

@ Dustin TY… as soon as at get gaskets, tmw, and get back together I’ll check those

 

[Texas Dave]

I know this is going to sound crazy...but I had the same exact issues with my 2007. I tried replacing coils and plugs and still had the problem. Someone told me to replace the gas cap. I did and the problem went away. I can stomp it to pass someone on the highway and it runs smooth and strong. Fortunately, in my situation, this was a cheap and easy fix.

 

[Planocat]

I feel your pain....experienced exact same issue on my 5.4L 3V. Literally spent thousands from the local mechanics parts cannon to no avail. I loved the truck and have it setup and accessorized just the way I wanted it. Being a stubborn old fart in my 70's, I wanted it to be my last truck. Boy, did I pay the price for that. I'm attaching a list from the parts cannon (please, no "what a ********" comments. I know, I know.

Resolution was reached by a young service writer at major Ford dealership during oil change discussion when he said..."Maybe you need a new set of eyes looking for the problem, we have couple of great techs and the equipment sophisticated enough to diagnose anything". I went home and thought about it. Came to the conclusion I had spent years and thousands to no avail. Made appointment with his Master Tech who was a couple of weeks out.

Received a call next day that he had it fixed but wanted permission to drive it home and back (about 150 miles) to be sure. Picked it up about 2 years and 45K ago and haven't seen the dreaded check engine light / misfire since. Had I taken it there in the first place, I wouldn't be writing this. But then I wouldn't have a truck where everything should be "good to go" for the next 230K. I attribute the cure to a very high dollar diagnostic machine and a great tech who was very conscientious and knew how to use it!

Here is the list of what was done BEFORE I brought it to the dealer. No one likes to spend $160 an hour labor, but it would have saved lots of money and heartache.

Hope this helps......



Maybe it's time for a new set of eyes on your vehicle.

Best of luck......
Planocat

 

[megan4221977]

@Planocat what was the issue he fixed?

 

[megan4221977]

@TexasDave doesn’t have a gas cap wish it was that simple

 

[Planocat]

At the end of the day, I think I received counterfeit coils and plugs off the internet from Walmart.com. Fordmakuloco has a youtube video on Motorcraft counterfeit parts and I believe that I was the victim as the whole issue started when I replaced all 8 plugs and coils with "genuine Motorcraft" parts not purchased directly from Ford. That all started the witch hunt for the vacuum leak, fuel pressure, etc. cause.

In addition, looking at the final cure from the dealership, that appears to be 2 coils and 2 plugs, I do not minimize the EEC diagnosis, Pinpoint Tests, and especially the update of the PCM. All I know is that at 231,000 miles it is the strongest running vehicle I own and hasn't missed a beat since Jan 2020.