Missing at high RPM

[Vols77]

My 4runner misses at 4000 RPM.

Runs great if you don't get the rpms that high but as soon as you hit 4000 it starts missing. Totally stock 3.4l with an automatic transmission. Not getting any codes.

Any ideas where to start?

Thanks

 

[dogtail]

My 4runner misses at 4000 RPM.

Runs great if you don't get the rpms that high but as soon as you hit 4000 it starts missing. Totally stock 3.4l with an automatic transmission. Not getting any codes.

Any ideas where to start?

Thanks

Does it seem like ignition issue or fuel issue? Start simple.
More likely ignition skip...bad plug wires and boots can arch at higher rpm. Look at the spark plug boots for age cracks. Wire sets dont come with coil boots so some people will not change them out. You can get oem Denso coil boots from Rockauto. Dont get cheap wires, the boots heat crack quickly on crap wires. Look at spark plug condition.

 

[Silver Supra]

Does it seem like ignition issue or fuel issue? Start simple.
More likely ignition skip...bad plug wires and boots can arch at higher rpm. Look at the spark plug boots for age cracks. Wire sets dont come with coil boots so some people will not change them out. You can get oem Denso coil boots from Rockauto. Dont get cheap wires, the boots heat crack quickly on crap wires. Look at spark plug condition.

Agreed, this sounds ignition related. How old are the plugs and wires?

 

[Tyler James Inc]

3rd for ignition. Likely a coil pack. Any misfire codes? If so, you can swap the coils around and see if the misfire follows the coil.
In my opinion- if you don't have record of them being replaced- you'd be better off just replacing the plugs, wires, and all 3 coil packs. I like to have a good baseline, and keep record of everything I replace. It makes future troubleshooting easier too. The coils aren't cheap, and don't go aftermarket. You're just asking for future headaches if you go aftermarket on electronics like that. Stick to Genuine Toyota parts for the plugs, wires, and coil packs. Lots of guys go with NGK. I'm sure they're fine, but personally, I hate the blue wires!
I actually just got my new Genuine Toyota wires in the mail yesterday [emoji1598]

 

[I_bRAD]

3rd for ignition. Likely a coil pack. Any misfire codes? If so, you can swap the coils around and see if the misfire follows the coil.
In my opinion- if you don't have record of them being replaced- you'd be better off just replacing the plugs, wires, and all 3 coil packs. I like to have a good baseline, and keep record of everything I replace. It makes future troubleshooting easier too. The coils aren't cheap, and don't go aftermarket. You're just asking for future headaches if you go aftermarket on electronics like that. Stick to Genuine Toyota parts for the plugs, wires, and coil packs. Lots of guys go with NGK. I'm sure they're fine, but personally, I hate the blue wires!
I actually just got my new Genuine Toyota wires in the mail yesterday [emoji1598]

Agreed. Had the same symptoms, no code. New wires didn't fix it (but didn't hurt) and new coil packs did. By the time I fixed it, it was starting to miss at lower speeds sometimes as well.

 

[dogtail]

3rd for ignition. Likely a coil pack. Any misfire codes? If so, you can swap the coils around and see if the misfire follows the coil.
In my opinion- if you don't have record of them being replaced- you'd be better off just replacing the plugs, wires, and all 3 coil packs. I like to have a good baseline, and keep record of everything I replace. It makes future troubleshooting easier too. The coils aren't cheap, and don't go aftermarket. You're just asking for future headaches if you go aftermarket on electronics like that. Stick to Genuine Toyota parts for the plugs, wires, and coil packs. Lots of guys go with NGK. I'm sure they're fine, but personally, I hate the blue wires!
I actually just got my new Genuine Toyota wires in the mail yesterday [emoji1598]

I have some spare parts rig ignition coils to swap out if I need them or need to test, cheaper than buying new in case I don't need them. The coil boots can be bought separately from the coils, although Autozone will tell you otherwise.

 

[Tyler James Inc]

I have some spare parts rig ignition coils to swap out if I need them or need to test, cheaper than buying new in case I don't need them. The coil boots can be bought separately from the coils, although Autozone will tell you otherwise.

I don't deal with auto parts stores at all, and if the boot is deteriorated to the point it needs replacing, I would rather just replace the whole coil.
Spare parts are definitely nice to have for troubleshooting!

 

[gamefreakgc]

Also a vote for ignition issues. Before you go out and replace all your coil packs though (not cheap) also check into your fuel filter and if it has ever been replaced. A clogged filter will limit fuel pressure at high demand situations, like over 4k RPM.

 

[dogtail]

I don't deal with auto parts stores at all, and if the boot is deteriorated to the point it needs replacing, I would rather just replace the whole coil.
Spare parts are definitely nice to have for troubleshooting!

I hear ya on crappy parts stores.
On the coil boots, optimal to be replaced with the wire set, only $32.79 for Denso set of 3 at Rockauto. Seems half baked if replacing 3 spark plug boots connected to the wire set and not replacing the other 3 spark plug boots connected to the coils.
https://www.rockauto.com/en/moreinfo.php?pk=1035296&cc=1357455&jsn=370&jsn=370&jsn=370

 

[Vols77]

Thanks for the tips. I don't know when the plugs were changed last so I'll start there.

Thanks again

 

[Vols77]

I took the 4runner into a shop. They replaced the spark splugs, fuel filter and air filter but still missing at 4k rpm. They are thinking it may be something wrong with the ecm. Still no codes.

Should I look into having the fuel pump swapped?

 

[Silver Supra]

I took the 4runner into a shop. They replaced the spark splugs, fuel filter and air filter but still missing at 4k rpm. They are thinking it may be something wrong with the ecm. Still no codes.

Should I look into having the fuel pump swapped?

Coils.... coils.... coils...

 

[Vols77]

Coils.... coils.... coils...

I brought that up but they said that would have generated a code....

 

[I_bRAD]

I brought that up but they said that would have generated a code....

coils and a new shop!

 

[Tyler James Inc]

coils and a new shop!

How you gonna feel when he takes it to the shop and spends $300+ on OEM coils to be installed and it still misses? [emoji30]
I also think it's a coil, I am just very hesitant to suggest things so strongly to guys if I'm not 100% positive it will resolve their issue- especially when they aren't doing the work themselves.
OP, if you were local to me, I would throw my coils on to help troubleshoot. Maybe there is someone local to you that would be willing to do the same. It's a very easy process.

 

[Vols77]

How you gonna feel when he takes it to the shop and spends $300+ on OEM coils to be installed and it still misses? [emoji30]
I also think it's a coil, I am just very hesitant to suggest things so strongly to guys if I'm not 100% positive it will resolve their issue- especially when they aren't doing the work themselves.
OP, if you were local to me, I would throw my coils on to help troubleshoot. Maybe there is someone local to you that would be willing to do the same. It's a very easy process.

I appreciate the tips.

Shouldn't it be shooting a code though? I'm only getting one code and it's a B2796 code. I almost think I'd be best off buying a coil and going through them one at a time to see if that stops the miss at 4k rpm.

 

[Tyler James Inc]

Shouldn't it be shooting a code though? I'm only getting one code and it's a B2796 code. I almost think I'd be best off buying a coil and going through them one at a time to see if that stops the miss at 4k rpm.

Yes, it should be. Which is why I can't say with 100% confidence it's a coil(even though I believe it is).
I agree; that would be a good way to troubleshoot your coils [emoji1360]