Intermittent misfire cyl 1 07 Yaris 1.5 sedan

[Toolaholic]

Hi all, I have replaced plugs ,coils, pvc valve, O2 sensor MAF sensor plus Techron fuel cleaner. Sprayed intake with carb cleaner no change in idle. It’s intermittent. Daughter drove it 50 miles and I got a a misfire reading of 334. And yes I know it’s a algorithm. I replaced plug and swapped a coil in. I drove it hard 3 times and got 69,77 and wait for it 1. I will post pics of changing a plug out in another thread.

[Toolaholic]

It idles smooth with air off. So smooth the steering wheel doesn’t vibrate at all .

[Toolaholic]

Daughter got back after 50 mile trip home. Cylinder 1 had reading of 1. I got it to 100 twice to get to the 6,000 rpm full throttle shift from 2nd to 3rd. Reading was 2 on cylinder 1. Now at some time later in the week she’ll come home and it will read 80 or something high like that. Unless the Techron works and it’s fixed. Makes no sense sometimes you flog it and get a 1. Sometimes a 69 or 77. It can take being run hard every now and again . Mobil 1 5w30 and amsoil in transmission plus cooling system serviced twice. Well taken care of.

[Toolaholic]

She taking it on a 100 mile trip to the beach then 100 back . Fingers crossed. Hoping the Techron fixed it and it was a plugged injector.

[Toolaholic]

It’s at martins auto center. They do outstanding work. Replaced intake manifold gasket. Still no improvement. It drives great for 20 minutes then misfires and flashes engine light on clylinder 1. Pull over for 5-10 minted and it runs great again for 20 minutes

[Toolaholic]

Garage called fuel injector

[Brighton]

If it's fuel injectors, you could try BG44K cleaner, if it's a matter of them being clogged/sticky that will help.

[Toolaholic]

If it's fuel injectors, you could try BG44K cleaner, if it's a matter of them being clogged/sticky that will help. used Techron 3 times. It runs awesome for 30 minutes at a time then misfires heavily . Runs great again after 5 minute break. They tested injector said it tested bad. I’m assuming with a multi meter. I should of tested it but assumed it ran too good to be injector . I thought it was electrical problem somewhere. $350 labor / parts . I could of did it myself but it was $100 to diagnose it. So $250 more to fix. Oh well I put everything else on.

[Brighton]

Sometimes it's worth it to just get a fresh set of eyes on a problem. I'd see if you could swap the injector to another location and see if the misfire CEL changes cylinders.

[thebarber]

swap the injectors between cyl 1 and 2 and coil from 1 to 3 and see if the issue moves.

[Toolaholic]

$284. $144 labor and $124.95 for injector. It was the injector on cylinder 1. Got a denso injector for $45 (eBay) and a fel pro cylinder head cover gasket set for $9 ( amazon) to have in hand should this happen again.

[thebarber]

Glad you found the issue

[mirageman]

With all resepect, I'm not trying to be an ash hole, but I have no idea what algorithm you are referring to in the original post. I am sure most people here don't know, either. Can you explain what a misfire reading of 334 means? 69,77 and 1? I'm no ASE certified tech, but I feel like I just walked into a different country! Hehe...