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Toyotapro
Toyotapro, ASE master tech
Category: Toyota
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Experience:  ASE Certified, 10+ years Lexus and Toyota Certified
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Toyota Sienna Misfire even after new plugs and wires

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Misfire even after new plugs and wires

Pavlin Koev :

Hi and Welcome to Just Answer! My name is XXXXX XXXXX I will do my best to help.

Pavlin Koev :

you will have to check compression, have you?

Pavlin Koev :

those coils must be checked for power supply, if power is there, then check if groung control from computer is there. coil ground has be pulsating.

Pavlin Koev :

also, injectors on those cylinders must check if working.

Pavlin Koev :

injectors have constant power to one of the wires and pulsating control ground on the other wire.

Pavlin Koev :

if wiring and power is is good, then comuter is malfunctioning.

Customer: replied 5 years ago.
We have checked compression. I did have the smell of gas a few days before I changed the plug wires. But I could not pinpoint it. The compression was 180 psi.

Hello and thank you for using just answer!

Has a scan tool been used to identify specifc cylinder # XXXXX misfires and when it happens on a DATA list? Did you replace the coild specific for cylinder # XXXXX&3 and did you try SWAPPING the coil from the variouse cylinders on the front to see if the codes change at all?

Customer: replied 5 years ago.
Yes I have swapped coil packs around and the misfire remains the same. I just keep thinking maybe a bad injector? or two? I really appreciate the extra time you are spending with me. Just never had to deal with this on a toyota before.
If you are confident that compression and spark are present on these 2 cylinders then yes a clogged or leaking injector is the likely cause.......the only other thing that I have run across on this particular engine is usually right after some major work is done on it.....there is a ground strap on the back top center of the intake manifold that is held in place by a 10mm bolt, if the intake was removed for any repairs and this was NOT resecured then I have seen this cause random misfires in this manner. The fuel injecotr on cylinder #3 would require intake manifold removal, what I would do here is swap injecotr #3 with cylinder 4 or 6 so that your 2 injectors in question will be easily accessable at the front and you can properly diagnose this before you pay for any new parts.
Toyotapro, ASE master tech
Category: Toyota
Satisfied Customers: 9974
Experience: ASE Certified, 10+ years Lexus and Toyota Certified
Toyotapro and 4 other Toyota Specialists are ready to help you
you should check coils and injectors pulses before taking engine apart.
Customer: replied 5 years ago.
Had misfire on cylinders 1 & 3. Changed all o-rings on fuel injectors. Took car on a 10 mile drive and it misfired all the way to the store. Shut engine off at store and checked codes because check engine light came on again. Misfire 1,3 &4. Erased codes let engine cool came out of store started engine and it ran perfect for about 8 miles. Then I started to feel some hesitation but not as bad. Check engine light came on again but the code this time was knock sensor no misfire. So far to date I have changed plug wires, plugs, 2 coils, pcv valve, and all o-rings on injectors. Don't really know if the knock sensor is something easy to replace or not. Not sure where to go from here???
What happend to you moving injectors around to put the suspected ones on the front bank?????? Are yu SURE that there int a P1354 code stored as well?
Customer: replied 5 years ago.
I moved the injectors around and was still coming up with the same codes for misfire. Nothing much has changed until I put new seals for all six injectors. Old seals were bad. Now the problem is less but not completely solved. Not sure where to go from here? Knock sensor was the last code I got.
I think I'm missing part of your story here. I need ALL code #'s