Cylinder 7 Misfire

Hello, I was wondering if anyone else has had this issue. After the truck sits for a while and then start it, the check engine, 4 lo and traction control lights start flashing. I read the code and it comes back cylinder 7 misfire. Took it to the shop and they checked spark plugs (all good), they switched the ignition coil to a different cylinder to see if the misfire followed. Nothing. The next thing they did was replace the injector and they thought that was going to solve the problem. No lights for about a week. Then one morning after sitting the lights come on again. Every time I clear the code it will drive fine. Anyone else have or know what I should do to solve the problem? Thanks!

 

Did the code change to the cylinder the coildwas swapped to? My 1Gen has had this several times over 250K miles. first sign is intermittent bucking under load then CEL light may flash or go steady. Sometimes it stays on sometimes it doesn't. I would replace that coil first and be sure to only use Denso not some off-brand made of Chinesium. Over the years I've had 5 OEM coils go bad and with the last one I changed out the entire bank so hopefully good for another 250K. They are about $50 at the Rock and don't for out discount code.

 

The misfire still stayed on cylinder 7 when the cylinder 7 ignition coil was moved to cylinder 3.

 

Did you ever find out what was the problem with the misfiring of cylinder 7?
im having the same issue with my 2014 and I did the same thing by switching the coil and spark plug with cylinder 1 but still get misfire on cylinder 7!

 

This is gonna sound dumb, but make sure they are actually switching out the cylinder 7 coil pack. Not all V8 motors cylinders are numbered the same.

 

Next step would be to check your wiring and ground via a test light or wire chaser and see if you have a break/chaffing somewhere in between. If nothing is found, then a compression test and borescope to check what's going on...

 

You also didn't list which motor you have 4.6, 4.7, 5.7? Don't even know which year your truck is.

 

2014, definitely not a 4.7. 50/50 on the other 2

 

My engine is 5.7L , and I used this diagram:
https://www.tundratalk.net/threads/3ur-fe-cylinder-and-ignition-coil-numbering.188626/#lg=thread-188626&slide=0

It shows the cylinder 7 ( driver side, last cylinder near the fire wall)
Is that correct??

 

Were the spark plugs covered in oil when they were checked? Broken valve spring? That’s more common on older 5.7s.

 

That diagram is correct.

 

The spark plug that i pulled from cylinder 7 was pretty clean, no oil or anything seen around it. The spark plug that i pulled from cylinders 1 was easily removed ( almost no force was used) had a black ( smoke marks around it) and the outside of the coil was stained from smoke. ( no oil stains, everything was dry)

 

Sorry, looked back at the OPs post, not the recent poster.

 

No worries, I've done the same.

 

By clean do you mean steam cleaned??
Not to make you work more, but have you checked the other sparks?? Or maybe swap sparks 2 and 7. See if it gets cleaned as well... you may have a blown head gasket. If 2 is dirty and you swap it with 7 and comes back clean, you may have a valley leak or blown head gasket.

 

I checked all the drivers side sparks 1,3,5&7 .
1 was dirty with black smokes ( I think the spark plug wasn’t installed correctly)
3,5&7 was clean ( just signs of being used, normal color)
I will try to get nr#2 and swap it out with 7 and see if it works.
Ps: thanks in advance for your advice.

 

I replaced the cylinder 7 spark plug with cylinder 4, erased the code and drove for 45 miles and I got again the same code misfire cylinder 7 .
I will change the coils 7 &4 today and see if the misfire goes to number 7 cylinder.

 

This is one time 'clean' is not good. Hope it isn't leaking coolant into that cylinder - how is the coolant level holding up - don't trust the reservoir check the main tank.

 

Coolant tank was low almost empty , and my heater wasn’t working properly.
I fielded up and seen no stains on my driveway,
I put a mark on the tank and I’m checking it daily for the past 5-6 days, it is pretty much on the mark +/- 1/2” when is hot.
Do you think I have a coolant leak? Is this common in this model? ( this is my first Toyota)

 

Ps: after I erase the code the truck runs normal, when the check engine light comes on the truck runs roughly.

 

I’ve seen reports of clogged cats causing a misfire too even if you’re not getting cat codes. Just throwing more things to consider out there.

 

Following up on the misfire on my truck. I got a test kit and checked the coolant gases and seemed like a head gasket issue.
I have the truck at local mechanic that confirmed that is a head gasket leak and expecting to get a price for the repair.
What is a reasonable price for this work?
And is this work can be done on a small shop ? This is the first time that I’ve got my truck to this mechanic and he seems pretty confident about doing the work but seems to be very young early 30s and I’m wondering if he really can do this job?

 

You might want to watch this: https://www.youtube.com/watch?v=dfGTI0sWozc

 

Fixing a blown head gasket on an aluminum engine is a crapshoot. Sorry you’re in this situation.

 

Maybe my views are different than most, but I don’t know how many head gaskets and engines I have done on Subarus and they are all aluminum. Given the example truck in the video I would absolutely run that with a set of ARP head studs and call it a day, but I am not a shop and don’t have anything to stand behind.

 

My understanding - the problem is you don’t know the extent of the damage until there is a ton of labor to tear it apart. If the head or block need machined - I’m pretty sure it’s game over as there aren’t varying thickness head gaskets to compensate for losing material making the surfaces flat again.

 

How many miles do you have on the engine? Sorry about the head gasket. Hopefully they can get you fixed up.

I also get a little nervous with young mechanics. All the stuff in life (the few things) that I am good at, I am only good at because I've been screwing up for years and years and I know exactly what not to do and how to not do it.

 

I can't disagree with you. If the motor has not overheated I would be far more confident in this repair. If it has been overheated I would at least take the heads to the local machine shop and have them check the deck and try to check the deck on the block. You are right, it is crap shoot for sure and paying someone else to do the labor to give it a try is roll of the dice for sure.

@John P
Where are you located?