Weird Power Hiccup

[SCLaunch]

2020 JTR. All stock. Noticed a weird what I would call power hiccups between 30 mph and 50 mph. Very hard to describe, but almost like trying to downshift, but not really...more of just a power hiccup like a push back in the seat, and then just keeps going. Happens every 5-10 seconds between in that mph range. Any ideas?? Will see if any weird obd codes, but I'm not seeing anything immediately, and just can't figure it out.

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[JTenn]

Auto or manual? Trans slippage possibly? Does it happen in any gear or only a certain one? If its auto try moving over to manual and force it hold a gear. Do the rpm's fluctuate when this happens? Could be something weird going on with the electronic gas pedal maybe. Just brain storming.

 

[SCLaunch]

Auto or manual? Trans slippage possibly? Does it happen in any gear or only a certain one? If its auto try moving over to manual and force it hold a gear. Do the rpm's fluctuate when this happens? Could be something weird going on with the electronic gas pedal maybe. Just brain storming.

Auto. Best guess is 3-4th gear. Didn't notice anything crazy with the rpm's. Did check and no codes thrown. Also started researching on some JL forums where similar issue. They were pointing to something with the clutch...maybe even a recall. Was going to research that a bit more. Arrrggh! Has been rock solid since I got it, so this is annoying!

 

[Max-t]

Hiccups are almost, well are always, misfires, and almost always coils. But I wouldn’t put anything past the computer controls doing something new and exciting.

They can go on for a long time without storing a code till they reach a threshold. Then you’ll likely get a flashing cel.

The dealer/mechanic can see them live and record them on a test drive with his software.

If it’s literally on shifting then it’s some sort of slippage. But lord knows.

I’ve also had a couple injectors fail and moments before they opened and topped off my cylinders with gas, they sputtered a bit.

 

[Hootbro]

Been more than a few posting about 3-4 shifting issues. For the warranty folks, they seem to throw a new valve body in with most having to have the transmission replaced anyways.

 

[ShadowsPapa]

Been more than a few posting about 3-4 shifting issues. For the warranty folks, they seem to throw a new valve body in with most having to have the transmission replaced anyways.

That's been my observation in more than one Jeep forum - 3-4 range issues.
The problem is that if a clutch is seen as applied, the pressure reaches it's accepted norm in the prescribed time it's not going to throw an error and slippage isn't "watched". Something can bind or catch in a clutch pack then grab and go, or slip, then grab and go with normal pressures (and that's been true for decades)

The dealer/mechanic can see them live and record them on a test drive with his software.

Extremely doubtful there will be a code for this issue unless it's a case of the clutch pack (or servo) not reaching prescribed pressure, or taking too long to fill and I have a feeling there aren't many techs that know about any of that anyway - not today, even though it can technically be tracked and recorded. (even with JSCAN as far as I know)

Hiccups are almost, well are always, misfires, and almost always coils.

No. Coil failures are and always have been pretty rare.
He'd know and feel a misfire and these record misfires at the drop of a hat - even if the MIL isn't set, it will be recorded. And it feels totally different than what people have been experiencing with the transmission thing.

Hootbro, once again, is following the right set of tracks, (as opposed to train tracks. Sorry, it's the new meds for the migraines and stuff)

 

[Max-t]

Hot take bro.

Coils fail…. All the frickin time. Like… all the time. Always all the time. Always called a hiccup.
Been replacing bad coil packs since about 1994 ? Ever since they went multi coil packs on almost everything.

just got “stranded” in the desert with 2 bad coils on a 21 Toyota with 30k miles.
Which is also why I say they could record it… as a bad coil will pop off as a misfire cyl x . Ya feel em for sometimes years before they get bad enough to throw codes.
Feels like a transmission issue. Noticeable under acceleration. Feels like it’s slipping a little at a time. Just loses acceleration very momentarily.

Never had a clutch pack fail other than just burn up and a lip which no one has ever described as a hiccup. But I heard someone describe a squeak as a beep the other day. And with the autos on these things… anything is likely not just possible. So who knows.

Hope your headaches get better. Maybe some vrylar or anxiolytics.

 

[ShadowsPapa]

Hot take bro.

Coils fail…. All the frickin time. Like… all the time. Always all the time. Always called a hiccup.
Been replacing bad coil packs since about 1994 ? Ever since they went multi coil packs on almost everything.

just got “stranded” in the desert with 2 bad coils on a 21 Toyota with 30k miles.
Which is also why I say they could record it… as a bad coil will pop off as a misfire cyl x . Ya feel em for sometimes years before they get bad enough to throw codes.
Feels like a transmission issue. Noticeable under acceleration. Feels like it’s slipping a little at a time. Just loses acceleration very momentarily.

Never had a clutch pack fail other than just burn up and a lip which no one has ever described as a hiccup. But I heard someone describe a squeak as a beep the other day. And with the autos on these things… anything is likely not just possible. So who knows.

Hope your headaches get better. Maybe some vrylar or anxiolytics.

You'll see misfires on a scope and in JSCAN. Yes, you will see them even if the MIL isn't set. Been there, done that.
Misfires feel very different from transmission issues. I'd see a misfire in a scope pattern really fast. It can't be an ignition misfire and not show in a scope pattern. I've worked decades as a troubleshooter (specializing in electric systems) and to this day, I scope ignition systems and can spot a stray misfire with ease.
I've not had a bad coil of any type in many years. Rare.
A misfire is not even like a transmission issue which is more of a slip and grab. Very different. I can easily feel the difference.

These are extremely sensitive about misfires and will catch those you don't really even feel. And if my scope was connected, I'd see it............

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