Chasing misfire

[Bad Luck]

There must be a procedure to manually reset it. Like my 94 xj it's a key and headlight off/on sequence. When you add higher performance goodies it's better to relearn from scratch and much quicker. I have awesome results doing this. I think I actually did this in my 2010 runner with a key and e brake sequence after servicing all PCM inputs now that I think back.. you can loan me your techstream though ��

Here's a 2000 FSM: Update your browser to use Google Drive, Docs, Sheets, Sites, Slides, and Forms - Google Drive Help No where in there does it have a procedure for resetting fuel trims or learned engine values. The learned engine values clear when the ECM loses power so either pulling the fuse or disconnecting the battery clears it.

 

[Jakeepoo3]

Here's a 2000 FSM: Update your browser to use Google Drive, Docs, Sheets, Sites, Slides, and Forms - Google Drive Help No where in there does it have a procedure for resetting fuel trims or learned engine values. The learned engine values clear when the ECM loses power so either pulling the fuse or disconnecting the battery clears it.

That has never worked for the 5th, it evens says that in the manual at least. I tried that for a couple days and it still didn't reset. I know my fsm doesn't mention the manual reset either. I imagine you'd have to think beyond a manual. How much y'all pay your managers, you hiring? Just kidding luckers! Here's is the manual procedure I used. Worked like yay it should be the same procedure for before 2000 to present. Only thing I do different than this describes is relearn park through 1 in 2wd, 4lo and 4hi following the procedure this explains. The difference was large and easily noticed right away. Then I was seeing way better gas mileage soon afterwards. Don't tell your associates haha.

https://www.google.com/search?q=2010+4runner+manual+sequence+pcm+reset&client=ms-android-verizon&sxsrf=ALiCzsY3-4QXAP_7oabKTHl3HdGiZuZNGw%3A1652735086132&ei=bryCYuPNB8bcqtsP9fmksAY&oq=2010+4runner+manual+sequence+pcm+reset&gs_lcp=ChNtb2JpbGUtZ3dzLXdpei1zZXJwEAM6BwgjELADECc6BwgAEEcQsAM6BwgjELACECc6BQgAEKIEOgQIHhAKSgQIQRgAUOwlWNleYKpiaAFwAXgAgAHEAYgBnguSAQM1LjiYAQCgAQHIAQnAAQE&sclient=mobile-gws-wiz-serp

 

[Bad Luck]

That has never worked for the 5th, it evens says that in the manual at least. I tried that for a couple days and it still didn't reset. I know my fsm doesn't mention the manual reset either. I imagine you'd have to think beyond a manual. How much y'all pay your managers, you hiring? Just kidding luckers! Here's is the manual procedure I used. Worked like yay it should be the same procedure for before 2000 to present. Only thing I do different than this describes is relearn park through 1 in 2wd, 4lo and 4hi following the procedure this explains. The difference was large and easily noticed right away. Then I was seeing way better gas mileage soon afterwards. Don't tell your associates haha.

https://www.google.com/search?q=2010+4runner+manual+sequence+pcm+reset&client=ms-android-verizon&sxsrf=ALiCzsY3-4QXAP_7oabKTHl3HdGiZuZNGw%3A1652735086132&ei=bryCYuPNB8bcqtsP9fmksAY&oq=2010+4runner+manual+sequence+pcm+reset&gs_lcp=ChNtb2JpbGUtZ3dzLXdpei1zZXJwEAM6BwgjELADECc6BwgAEEcQsAM6BwgjELACECc6BQgAEKIEOgQIHhAKSgQIQRgAUOwlWNleYKpiaAFwAXgAgAHEAYgBnguSAQM1LjiYAQCgAQHIAQnAAQE&sclient=mobile-gws-wiz-serp

I'm glad that works for you, but what I'm telling you is what works for 3rd gens. I have watched the data via techstream before and after resetting the learned values. FYI I don't work at Toyota. I purchased a shitty laptop with a cd drive, a crappy obd2 to usb cable, and pirated techstream software with terrible installation instructions from Alibaba. It works, but it's not pretty to look at.

 

[3bears]

if you decide to go rebuilt or new injectors....motorwest...its even who timmy uses. I have used 2 set of theirs, about to order another set , all different rigs of course.

 

[TW44LR]

Just go back to basics:

Fuel +
Air +
Compression +
Spark +
All occuring at the proper time =
Normal running engine.

Sounds like you did spark-nope.
Air is unlikely an issue-nope.
Timing (both valve timing and spark timing) is probably not it since it’s one cylinder mostly and generally one major failure would affect more than one cylinder-nope.
So now you’re down to compression and fuel.

Compression testers are cheap, may even be rentable. I doubt it’s a compression issue since it’s intermittent and generally a compression issue is constant. But you could try.

That leaves fuel. This is further broken down into supply and delivery.
Unlikely a supply problem (pump, filter, bad gas, low pressure etc) since, again, it’s a single cylinder and generally an overall supply issue would affect more than one.

So now it’s down to delivery: injector, computer, wiring in between. You could install a little light bulb (special version is called a noid light) piggy-backed onto the wires of the suspected injector and look for a flashing bulb WHILE THE MISFIRE OCCURS. This would rule out the computer and harness. You want to see a flashing light (which is a command to fire the injector) WHILE MISFIRING. Means the injector is no good. Now, a non flashing light would lean towards a harness or computer issue.

It’s probably the injector. Had a similar issue back in 2020. Went through all the same steps since I already have all the tools. It’s about the same amount of time to do one injector vs all. All injectors are same age, same amount of cycles. So I’d say do them all if you settle on injectors.

I went through 5-0 motorsports. Small deposit to return old injectors. They’re reman’d OEM.

Thank you for the information, this confirms my thinking as well. I’ll look at 5-0 motor sports


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[TW44LR]

if you decide to go rebuilt or new injectors....motorwest...its even who timmy uses. I have used 2 set of theirs, about to order another set , all different rigs of course.

Thanks 3bears, have heard their name for sure, will check it out.


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[TW44LR]

It's up to you. I have had a misfire and replaced injector 3 with oem and have added close to 100k miles without any issues.

Gotcha, thanks for the info


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[brillo_76]

Oh. If the injector is plugged you probably not get it unplugged that quickly. I can't say if it helps. I myself just run some injector cleaner a few tanks a year on all my rigs. So far I haven't has to change injectors.
Maybe it's just been luck for 30 years. Who really knows.

If everything is checking out. It's very possible your one injector is intermittently failing on you.

Fuel pressure check is shown how to do in the factory service manual.

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[TW44LR]

Oh. If the injector is plugged you probably not get it unplugged that quickly. I can't say if it helps. I myself just run some injector cleaner a few tanks a year on all my rigs. So far I haven't has to change injectors.
Maybe it's just been luck for 30 years. Who really knows.

If everything is checking out. It's very possible your one injector is intermittently failing on you.

Fuel pressure check is shown how to do in the factory service manual.

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Thanks Brillo appreciate all the help here and all the knowledge throughout the rest of the forum!


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[Jakeepoo3]

Gotcha I’ll try to test it this weekend. If it tests bad should I go ahead and replace them all or just the one? Any good sources on where to get them?


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With the suspected injector pulled out of the rail connect 12 volt power source to one terminal at the connector and ground wire to the other terminal. The injector should click each time the ground wire is connected and disconnected to the terminal.

 

[IBallEngineer]

With the suspected injector pulled out of the rail connect 12 volt power source to one terminal at the connector and ground wire to the other terminal. The injector should click each time the ground wire is connected and disconnected to the terminal.

Making the electromagnet click does not assure you the injector is properly opening the needle valve at the rate required or that the spring is returning it to fully closed. If you have the injector out, replace it! I know it 's pricey, but replace them all, don't buy cheap. And no matter what replace ALL THE INJECTOR SEALS. Be sure to use a lubricant on the seals when reinstalling the fuel rail. Pressurize the fuel system before you re-install the intake plenum and make sure you don't have any leaks. The seals are fragile and easily ruined.

 

[jhuerta22]

Gotcha I’ll try to test it this weekend. If it tests bad should I go ahead and replace them all or just the one? Any good sources on where to get them?

I bought OEM off of ebay used. I only replaced the bad one a the time since the others were in spec. You could replace all of them and if you buy used, test them before install. I know it sounds like a duh statement, but I had an issue with a new OEM TPS which wasn't working and ended up having to get another to fix my problem.

 

[dvachon]

I bought OEM off of ebay used. I only replaced the bad one a the time since the others were in spec. You could replace all of them and if you buy used, test them before install. I know it sounds like a duh statement, but I had an issue with a new OEM TPS which wasn't working and ended up having to get another to fix my problem.

thanks