2008 -- Once warm won't rev past 3000rpm

[Faulteh]

Hey all,

So, I've done some searching and some reading already but most people I talk to suggest starting to replace parts. I'm looking to sell this car for like $2500-$3000 so, starting to swap parts really doesn't make sense for me. I'd like to find a way to diagnose what's wrong with my car and fix JUST that.

So, my car is a 5 speed, ~188,000 KMs.(117,000 miles).. It's developped a fun issue where on a cold start, it tends to drive fine. Then after ~10 minutes, it won't rev past 3000RPM. The tach just bounces off and it feels like the car stumbles. It will do this continously if you keep it at 3000rpm, if you upshift before this issue you can avoid it completely.

Only thing I've done so far is take the MAF off and spray it with sensorkleen.

Note: I am a COMPLETE noob when it comes to repairing cars. But, I do troubleshoot for a living, so I think I have the mind for it and am open to doing the work and learning to get this fixed.

So far, I've seen people suggest the most likely causes are:

1) spark plugs
2) ignition coil
3) fuel filter
4) catalytic converter

What i'd like to know is. How do I diagnose these issues and verify that's the problem without starting to swap parts. Should I remove the spark plugs and inspect for burns/cracks? If I do, should I have anti-seize on hand to reapply?

I'm happy for anyone's help!

Thanks!

[myfirstyota]

No engine light by chance?

[Leegamer]

That sounds like a MAF or ignition issue to me. +1 on if you have a CEL.

I would also just remove the negative battery terminal and let the ECU reset just for the heck of it.

[Faulteh]

No check engine light.

So question is, how do I troubleshoot it? Can I swap with a MAF from an newer yaris model,, like a 2004, 2005?

can I disconnect the MAF to see if the issue changes?

[tmontague]

Also potential fuel shortage, check fuel pressure if possible

[Faulteh]

Also potential fuel shortage, check fuel pressure if possible

how?

[tmontague]

no easy way other than hooking up a fuel pressure sensor. Bad fuel pumps typically cause low power when you open up the throttle as that is when fuel demand is at its highest

fuel issues don't really trigger a CEL as often as an ignition issue does such as a misfire and you don't have any CEL's

[2bz]

Buy a OBD2 reader. https://www.amazon.com/OBD2-Scanner-OBDII-Code-Reader/dp/B0743X5WV8

FWIW, My guess are the coil packs.

[Faulteh]

Also potential fuel shortage, check fuel pressure if possible

Buy a OBD2 reader. https://www.amazon.com/OBD2-Scanner-OBDII-Code-Reader/dp/B0743X5WV8

FWIW, My guess are the coil packs.

doesn't this only work if I have a check engine light/ code is thrown?

[tmontague]

If it is a misfire due to ignition, you would have a CEL and therefore a code to read. Without it I would guess fuel issue although not common on the yaris

[Faulteh]

If it is a misfire due to ignition, you would have a CEL and therefore a code to read. Without it I would guess fuel issue although not common on the yaris

Is this 100%? I see multiple videos on youtube where people had ignition coil issues and the CEL never came on.

I may just get some plugs, and 1 coil pack, and rotate it through each cylinder. If it doesn't solve the problem, I'm just going to dump it for like 2k. Otherwise, I'll end up spending 100's on labour on a car selling for less than 3k.

Also this only occurs once the car has been driving for like ~10 mins. Does that sound like a fuel pump?

[tmontague]

Is this 100%? I see multiple videos on youtube where people had ignition coil issues and the CEL never came on.

I may just get some plugs, and 1 coil pack, and rotate it through each cylinder. If it doesn't solve the problem, I'm just going to dump it for like 2k. Otherwise, I'll end up spending 100's on labour on a car selling for less than 3k.

Also this only occurs once the car has been driving for like ~10 mins. Does that sound like a fuel pump?

Well why would you be driving a cold engine harder than 3k rpm? That's likely why it doesn't seem to happen right away. That said, heat from an engine can also make a coil act up when it's on it's way out. How old are the plugs on the car?

And no, of course nothing with cars is going to be 100%, there will always be outliers. But how will a bad coil pack cause a huge misfire to where the car wont even accelerate but somehow doesnt trigger a single cylinder or multiple cylinder misfire code? Typically it will throw a single cylinder code as well as a multiple cylinder misfire code.

Up to you where you want to put the money but it can get expensive throwing parts at it and seeing what sticks. Have you ever actually hooked a scanner up to the car or are you just basing it off of not seeing a CEL? Does the CEL momentarily illuminate when you turn the car on? The catalytic converter is also a potential cause of your issues.

If people tell you to start replacing parts without knowing what is wrong in the first place walk away very slowly...

If you do get it figured out, let us know then issue

[ex-x-fire]

I've had bad maf sensors on cars, they actually ran better with the maf unplugged. You can try unplugging it and take it for a ride.

[Faulteh]

I've had bad maf sensors on cars, they actually ran better with the maf unplugged. You can try unplugging it and take it for a ride.

if I unplug it. The car will not start.

I took it for a drive today, on the off chance the CEL light would come on. It did not, but it was starting to miss, so I figured I'd pull over, and look at some stuff.

I pulled over and popped the hood. I had turned the car off through force of habit and when I tried to start it.. Engine would crank and crank but never fire up.

So, it had done this 1 other time. So I just let it sit for 5 minutes. After that it would start. So I figured, ok, lets take it for a ride with the MAF unplugged.

I unplugged the MAF sensor and started it up. It would seem to start, then the TAC would drop to 0 and the engine would stop.

Plug the MAF back in, and it started. (did this twice to confirm it wasn't a fluke)

Drove it home.....

[dogsridewith]

Maybe a double signal is getting to the 6k rpm rev limiter.

[IllusionX]

if I unplug it. The car will not start.



I took it for a drive today, on the off chance the CEL light would come on. It did not, but it was starting to miss, so I figured I'd pull over, and look at some stuff.



I pulled over and popped the hood. I had turned the car off through force of habit and when I tried to start it.. Engine would crank and crank but never fire up.



So, it had done this 1 other time. So I just let it sit for 5 minutes. After that it would start. So I figured, ok, lets take it for a ride with the MAF unplugged.



I unplugged the MAF sensor and started it up. It would seem to start, then the TAC would drop to 0 and the engine would stop.



Plug the MAF back in, and it started. (did this twice to confirm it wasn't a fluke)



Drove it home.....Where in Canada are you located?

Sent from my CLT-L04 using Tapatalk

[Faulteh]

Saint John NB

[2bz]

Buy a OBD2 reader. https://www.amazon.com/OBD2-Scanner-.../dp/B0743X5WV8

Or you can keep guessing and maybe figure it our by chance!!!!

[Faulteh]

Will this help me figure it out by reading values or only help if I have a check engine light on?

[IllusionX]

Will this help me figure it out by reading values or only help if I have a check engine light on?I think you should just get rid of it, or fix it.

Get it tested. They will take an hour or so to run some tests and you'll be 150$ short so you know how low you should sell your car for.

Sent from my CLT-L04 using Tapatalk

[Faulteh]

I bought a scanner and will be running through https://youtu.be/RZ_DLBQN548 to see if it is indeed a misfire.

[Faulteh]

Just a follow up. I put some STP water remover in the gas and the issue is almost entirely gone. The car did sit for a couple weeks with some crazy temp swings so it may have just been condensation.

[Leegamer]

That's weird. It sounds like some kind of limp mode for sure.

[Faulteh]

Hey all!

Me again! Yep,,,, this saga continues. The issue returned and I got an odb2 scanner on the thing.

I get random cylinder misfires across all cylinders.

I checked the o2 sensors and sensor 1 bank 1 returns no data at all and sensor 1 bank 2 returns data I don't really know how to interpret.



Getting no data from Bank 1, does this suggest my O2 sensor is dead?

[IllusionX]

There is an upstream o2 sensor and a downstream o2 sensor.
I'm not sure if you should be able to read data from both, but if it was a bad o2, I'm pretty sure you would get a code. A bad o2 would also get you into limp mode, which would prevent engine to rev as well...

Sent from my CLT-L04 using Tapatalk

[tmontague]

My ultragauge receive data from both so there is something odd for sure. But why you don't have a CEL is beyond me

[TypeReaL]

vvti solenoid check that my fathers yaris had the same not reving past a certian point, I managed to check that after thinking it was similar to vtec not crossing over on a honda it basically as a protection it will rev to the point where it should cross over and keep going but instead fall flat on its face

[TypeReaL]

https://www.ebay.com/p/TOYOTA-1nzfe-Camshaft-Timing-Oil-Control-Valve-Factory-Solenoid-VVT-15330-21011/656532936