Misfire First Cylinder.

[Zoey1]

Good evening,
currently I own a 2012 Toyota Venza LE 4 cylinder 126k miles. January this fiscal year I’d experienced a misfire on the first cylinder.
This past April, I’d Replacing 4 engine coils, 4 spark plugs and flushed the engine. Upgrade the gas detergent from 87 to 89

Since then the car was running perfect until
this past August, back to square one, a misfire on the first cylinder. I changed all 4 spark plugs and all 4 engine coils... unfortunately it’s still a misfire.

please advise?

 

[Lubener]

I would swap the number one coil with another cylinder first and recheck codes..If the code stays the same,then I would swap the number one fuel injector with another cylinder andsee if thecode follows the injector or stays with the cylinder.

 

[Astro14]

Good advice, there.

In the meantime, this question belongs in the mechanical/maintenance forum, so I’m moving it.

 

[JT20]

If your coil or injector (probably coil) doesn't solve the problem then you've got some engine issues.

I am worried for you now because you said you changed already. Really should change all at once, coils.

 

[mk378]

Compression test. This may find a mechanical problem.
Then try swapping injectors as suggested.
If misfire occurs at idle, check for intake air leaks near the cylinder affected

 

[Zoey1]

I would swap the number one coil with another cylinder first and recheck codes..If the code stays the same,then I would swap the number one fuel injector with another cylinder andsee if thecode follows the injector or stays with the cylinder.

I give it a shot and circle back with you with results.

Thank you

 

[Trav]

Good evening,
currently I own a 2012 Toyota Venza LE 4 cylinder 126k miles. January this fiscal year I’d experienced a misfire on the first cylinder.
This past April, I’d Replacing 4 engine coils, 4 spark plugs and flushed the engine. Upgrade the gas detergent from 87 to 89

Since then the car was running perfect until
this past August, back to square one, a misfire on the first cylinder. I changed all 4 spark plugs and all 4 engine coils... unfortunately it’s still a misfire.

please advise?

You need to do a leak down test along with the compression test. The Denso injectors used on this engine are somewhat prone to clogging at higher miles as there is no filter in them and the nozzle holes are very small but I would suspect the injector manifold seal more, they dry out and crack causing a vacuum leak. Let me know if you need new ones I have them and would be happy to send you 4.

If moving the coils around doesn't identify the issue and compression and leak down is good check the fuel pressure and the injector manifold seals.
Low fuel pressure usually results in multiple cyl misfires but sometimes the weakest link in the chain is what gives up the ghost and misfires.

 

[Zoey1]

Please see attachment,
This is the result after one week before changing again.

 

[Astro14]

How long (miles/time) has that plug been in there? That is way rich, or has a big oil leak into that cylinder...

 

[Zoey1]

126k
Plug been charged twice since April

 

[Astro14]

So, on that plug, what, 2,000 miles? That’s concerning...

 

[Zoey1]

Oil was changed consistently since 2015, every 3k miles.
The first misfired occurred Jan 2020...
Flushed the engine and changed our 4 plugs in April and 2 more again in August.

 

[Zoey1]

So, on that plug, what, 2,000 miles? That’s concerning...

No.... less then 300 miles

 

[mk378]

Are the other 3 plugs like that? Does the car make smoke from the tailpipe, and if so what color is the smoke?

 

[Nick1994]

Oil was changed consistently since 2015, every 3k miles.
The first misfired occurred Jan 2020...
Flushed the engine and changed our 4 plugs in April and 2 more again in August.

That's not good.

Might want to do a piston soak, similar to what they do to the oil burning Saturns. See if it'll get the CEL to go away and trade it in.

 

[Zoey1]

Are the other 3 like that?

Just the 1st

That's not good.

Might want to do a piston soak, similar to what they do to the oil burning Saturns. See if it'll get the CEL to go away and trade it in.

would you recommend Seafoam?

 

[ripcord]

Is this engine using oil? That is way too much fouling on that plug for 300 miles.

 

[Nick1994]

Just the 1st

would you recommend Seafoam?

Probably B12 Chemtool. I think the trick is to pull the plug and pour some down the hole and let it soak for a while. Then crank with no plug to blow out the Chemtool and then put back together.

I'll let others chime in though.

 

[mattd]

If this is a 2.4L they are known for oil use. You probably have stuck rings on that cylinder. I would do a leak down test to rule out valve sealing but not likely.

Either way if it oil fouls that plug that fast you have a mechanical issue. It’s going to be a costly repair.

 

[ripcord]

What mattd said.