Truck "bucks" at slow, steady speeds

[Jmckinley]

Definitely look at the Differential Pressure Sensor in the EGR system as mentioned previously and in another thread as shown above. Valve is not expensive and sits on top of the engine where it's easy to access. Dealers are mostly clueless about this sensor fix which is odd because if you do a search you'll see that it has been problematic for years on a variety of Ford engines.

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[fjwlobo]

I have a 2020 Lariat FX-4 with around 6100 miles on it. I'm about 5 miles from work and most of my drive is in the 25 - 35 MPH range.

You probably don't have anything wrong with your transmission.

FORD NEEDS TO REPROGRAM THE TRANSMISSION SHIFT POINTS AT SLOWER SPEEDS!!!

Something you can try. Put the transmission in DRIVE and push the the manual shift button on the side of gear shift stick up or down. You'll see on the right display what gear the transmission is in (this will not shift the transmission unless you're in MANUAL). When I'm going around a steady 30 mph; the transmission on my truck goes to 7th gear (too high for this speed in my opinion). This is more than likely why you're also having that bucking feeling. The RPM drops too low and the transmission will not shift down unless you accelerate. The only thing you can try to stop the bucking feeling is to put the transmission in MANUAL and shift to 5th gear (or maybe 6th gear at the most). The engine will run around 2000 RPM and you'll be around 30 - 33 MPH. Put back in DRIVE when slowing to stop or manually down shift and repeat. Yes, this shouldn't need to be done and is a royal pain in the @$$. Something else you'll notice is the transmission will shift from 1st to 3rd gear under normal acceleration skipping 2nd gear.

Hope this helps ?

 

[WNCblueridge]

It's not unheard of to have to walnut blast DI engines every 50k miles.

Sounds expensive?

 

[WNCblueridge]

How much did all that run you at your dealer?

Good to hear you got it resolved and still running well at 90k miles

 

[Vitis805]

Not sure what "bucking" means but I had some slight jerky motion at low speed that was fixed by relubrication of the driveline splines. "Bucking" sounds a little more severe than what I was experiencing, however.

Yes it's hard to tell and compare exactly what people are experiencing without being in their truck. I know my truck has some jerky motions at low speed, and I would certainly call it "bucking" when I am towing or have a load while stopping & going on an incline. I did the re-program TSB, that helped a little bit. My transmission was under-filled from factory so adding a quart helped a little bit more, and re-lubing the splines helped the most. At this point I will side with the techs and say that the transmission is just beefy for our 2.3L output (especially without boost, which makes sense because it happens at times when the drivetrain is most likely working without boost) and that the "jerking" or "bucking" is just the nature of the beast. Most people on here acknowledge that the remedy is more throttle, which again, makes sense. More throttle = more power to the transmission = smoother operation.

 

[doug910]

Yes it's hard to tell and compare exactly what people are experiencing without being in their truck. I know my truck has some jerky motions at low speed, and I would certainly call it "bucking" when I am towing or have a load while stopping & going on an incline. I did the re-program TSB, that helped a little bit. My transmission was under-filled from factory so adding a quart helped a little bit more, and re-lubing the splines helped the most. At this point I will side with the techs and say that the transmission is just beefy for our 2.3L output (especially without boost, which makes sense because it happens at times when the drivetrain is most likely working without boost) and that the "jerking" or "bucking" is just the nature of the beast. Most people on here acknowledge that the remedy is more throttle, which again, makes sense. More throttle = more power to the transmission = smoother operation.

In my case, it felt like an engine bucking when you're too high in the gears in a manual. It essentially felt like the engine was getting bogged down. My initial thought was that the transmission calibration got messed up and it was locking the torque converter too early. Turns out it was just misfiring under specific load conditions that cleared when I gave it more throttle.

 

[Vitis805]

In my case, it felt like an engine bucking when you're too high in the gears in a manual. It essentially felt like the engine was getting bogged down. My initial thought was that the transmission calibration got messed up and it was locking the torque converter too early. Turns out it was just misfiring under specific load conditions that cleared when I gave it more throttle.

I know exactly the feeling you are describing and have not had that particular experience with my Ranger.

Does the truck still do this? Was anything replaced or repaired?

EDIT: Sorry I just went through the EGR thread. Good info! Glad to know yours was just plugs. If I ever come across the situation I know where to start first.

 

[Nils]

How much did all that run you at your dealer?

Doug, I have an extended warranty (3 yrs 100k miles) so everything but the plugs and coils were covered.

 

[Gmacjr2112]

I have this same exact problem. Mine is a 2019 2wd at 48k miles. I've always ran premium 93 octane. All stock other than suspension. Started doing it around 40k. I've been to 3 different dealerships and they can't seem to find a problem. I can even set my cruise control at 30mph, let it ride steady and it will buck/jerk/skip whatever you want to call it. Runs just fine when I'm accelerating. No engine lights or codes. It's driving me crazy and I have no idea what to do about it.

 

[FX4Offroad]

I have this same exact problem. Mine is a 2019 2wd at 48k miles. I've always ran premium 93 octane. All stock other than suspension. Started doing it around 40k. I've been to 3 different dealerships and they can't seem to find a problem. I can even set my cruise control at 30mph, let it ride steady and it will buck/jerk/skip whatever you want to call it. Runs just fine when I'm accelerating. No engine lights or codes. It's driving me crazy and I have no idea what to do about it.

My dealer is telling me it's the torque converter. They tell me they have to open it up to verify but they've had it for a week and haven't taken it apart yet.

Every day I call them for an update they tell me they will have it on the rack "tomorrow". Every day... Tomorrow.

I'm picking it up tomorrow because I need it. I am moving and I need my truck.

Kinda pissed.

 

[Gmacjr2112]

My dealer is telling me it's the torque converter. They tell me they have to open it up to verify but they've had it for a week and haven't taken it apart yet.

Every day I call them for an update they tell me they will have it on the rack "tomorrow". Every day... Tomorrow.

I'm picking it up tomorrow because I need it. I am moving and I need my truck.

Kinda pissed.

Man that really sucks! I love these trucks and other than that mine runs perfect! So far I'm just not impressed with how Ford is handling these cases.

 

[FX4Offroad]

Follow up:
I just had the torque converter replaced in my truck and it did not solve the problem. It's still bucks at slow, steady speeds.
Other than that one issue, it runs fine in every other circumstance. Shifts fine, tows fine, runs fine.
Very frustrating

 

[FX4Offroad]

Update:
Bucking problem resolved.

So, you all know my frustrating experience.

Recap:
The dealer had my truck for a few weeks. They drove it, and diagnosed it. They determined that it was a bad torque converter. 57,000 miles.

I told the service advisor that my "guys" all agreed it was the EGR sensor. I was told it couldn't be that... It was the torque converter.

They changed that with many other parts. In total, they had my truck for 3 weeks

Picked it up and went on my way.

Absolutely no difference with the bucking - exactly the same as before the repair.

Update:
So I took it back. They had it for another week as they brought in a "driveability guy".

Got it back today, finally fixed.

It was the EGR sensor. $10.49 part when Googled.

 

[AzScorpion]

Update:
Bucking problem resolved.

So, you all know my frustrating experience.

The dealer had my truck for a few weeks. They drove it, and diagnosed it. They determined that it was a bad torque converter. 57,000 miles.

I told the service advisor that my "guys" all agreed it was the EGR sensor. I was told it couldn't be that... It was the torque converter.

They changed that with many other parts. In total, they had my truck for 3 weeks

Picked it up and went on my way.

Absolutely no difference with the bucking - exactly the same as before the repair.

So I took it back. They had it for another week as they brought in a "driveability guy".

Got it back today, finally fixed.

It was the EGR sensor. $10.49 part when Googled.

Glad you finally got it fixed right and a new TC out of it too. lol I ordered an EGR valve to have on hand as it seems imminent this WILL happen soon. They're on national back order but should be off by next week.

 

[Kingmm]

Thank you for the follow-up and summary. Very helpful as I navigate the exact same issue with my 2019 Ranger Lariat. Can you confirm which EGR sensor they replaced? Was it the pressure, heat, or the flow sensor?

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