Strange behavior with cruise?

[Enitan]

So I’m an avid fan of cruise. Tons of reasons but I’ve been noticing something of late:

In town I set it to 34mph. It feels like I’m riding in a bronco bull.

best way I can describe it is well jerky.

on the highway at 70 cruise is smooth as a babies backside, in town I feel a jerky feeling from the engine every 5-10 sec. the RPM don’t go up, the truck stays in 6th or 7th. But the whole way it feels like the truck is jerking and twitching.

this only happens in town with cruise set below 40. Anything above 45 still smooth as glass.

happens when motor is cold, warm and ‘normal’

it’s almost like the truck doesn’t know what to do on a level at 35 mph cruise. Just constant jerks like it wants to accelerate but doesn’t.

like I said RPM don’t go up, truck maintains speed just feels like riding on a wild horse in town with the cruise.

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[Deleted member 1634]

I'll say that I've set my cruise at 35mph before (keeps me from going too fast in areas of town where the 30mph speed limit seems too slow so you have a tendency to want to go faster), and it's always been smooth operation of the cruise system. I have an XLT with just regular cruise (not adaptive). So I guess I would say it's not a normal tick of the cruise control system, there might be something else wrong with your truck specifically.

 

[Rp930]

Have you tried increasing the distance setting ?

 

[Enitan]

Sorry y’all passed out mass reply inbound

I'll say that I've set my cruise at 35mph before (keeps me from going too fast in areas of town where the 30mph speed limit seems too slow so you have a tendency to want to go faster), and it's always been smooth operation of the cruise system. I have an XLT with just regular cruise (not adaptive). So I guess I would say it's not a normal tick of the cruise control system, there might be something else wrong with your truck specifically.

I do have the adaptive cruise but when I go out in the small town I’m basically the only car on the road. And nothing indicating it’s picking up a vehicle in front of me in the display.

i would agree there is probably something specific on your's

ive done cruise at slower speeds as well and haven't noticed it as you describe.

being in 6th or 7th, you may be in a specific torque point of the curve, and maybe you're feeling amplified adjustments that you normally dont feel at lower/higher torq settings.
I would play around with it my manually selecting a gear and see if it's better or worse.

I’ll toy with the gears tonight when I go out. I don’t notice it at all with cruse settings at 45 50 55 60 65 70 or 75 (have tested those so far here and they’re smooth as glass)

It’s hard to describe almost like it’s wanting to give it some gas but it decides not to mid go almost like for lack of a better word a “twitch” the RPM don’t move one bit but you can feel the truck do it.

I did experiment with just using my foot to maintain 35 in the same conditions and got no such feeling at all.

Have you tried increasing the distance setting ?

The times I’ve experienced this are late at night with no cars in front or even around. When I’m on the highway adaptive works perfectly and I don’t see the behavior. Though I am going a lot faster then so idk.

 

[Enitan]

So went out and experimented a bit

35mph cruise set on levels - twitch/jerk is there every 5-10 seconds

35mph cruise set on slightly varying road elevation - smooth as glass

60mph cruise set on levels - smooth as glass

60mph cruise set on slightly varying road elevation - smooth as glass

————

When I’m on the levels at 35 or 30 as soon as I hit any kind of climb or down hill no twitch. As soon as back on levels for more than 20-30 seconds it returns.

————

Experimented with gear limiter 5th it’s slight, 6th more noticeable, 7th def present, shifting into sport and forcing 8th same as 7th

————

I’m wondering if maybe a signal for acceleration is some how hiccuping along the way at low speeds. No dummy lights or error codes. Diagnostics mode has no stored errors either.

It’s pretty recent I’d say popped up over the last few hundred miles. I have an appointment for glass replacement (under warranty that’s an odd one but not a fault of the truck in anyway) hoping to maybe have something to give them to check out?

At this point I got nothing other than a perplexed look.

 

[Rene Michaels]

I use my cruise all the time and have not experienced that. I have a couple school zones on the way to work and set it at 20MPH with no hiccups as you described. Maybe you just have a bug on your windshield in front of the camera?

I will say I'm not yet a fan of the adaptive cruise. After all it is an AI and the timing of the braking is just not human-like. I had a instance when a car on my right moved into my lane and the adaptive cruise hit the brakes pretty hard. For a brief moment I was worried the guy behind me was going to rear-end me. Thing is, I didn't react because the car that moved into my lane was accelerating and probably 5-6 car lengths ahead of me, but the AI decided to do it for me. My human reaction would have been to take my foot of the gas as I did not need to brake. I had the distance at minimum when this happened.

I don't trust cameras or sensors on any vehicle yet. Crazy unpredictable things they are!

 

[James Plastina]

I'm having this same exact problem on my truck. level ground under 40mph. Very jerky. Bucking back and forth just how you explained it. The other day it did the jerking and then the engine died for 2 seconds then came back. I'm so confused at how to deal with this issue. I'm going to drive it to the dealer and start asking for answers because this is BS..

 

[P. A. Schilke]

I'm having this same exact problem on my truck. level ground under 40mph. Very jerky. Bucking back and forth just how you explained it. The other day it did the jerking and then the engine died for 2 seconds then came back. I'm so confused at how to deal with this issue. I'm going to drive it to the dealer and start asking for answers because this is BS..

Hi James,

Have you verified this condition exists with regular Cruise? If it is okay, then there is something out of whack with adaptive cruise.. The answer to this question might help the dealership diagnostics.

My truck works just fine, but I have adaptive cruise disabled...I hate it with a passion...

Back Story:

Ford Truck started offering Cruise control on high trim level trucks in the early 70s. Many of the old times snorted at this candyass addition, but we forged ahead. It was on auto trans XLTs, the top trim level. It was so unsophisticated that at low speeds it caused a bucking bronco effect. Seems the vehicle sensor would detect a dip in set speed and the vehicle would go to Wide Open Throttle..OOPs...too much speed gain..so Closed throttle...OOPs...Too low...back to WOT...and so on.... Made it very limited as to when it actually worked as is should. Modern Cruise is so much better!

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[Stephen Abbene]

Hi James,

Have you verified this condition exists with regular Cruise? If it is okay, then there is something out of whack with adaptive cruise.. The answer to this question might help the dealership diagnostics.

My truck works just fine, but I have adaptive cruise disabled...I hate it with a passion...

Back Story:

Ford Truck started offering Cruise control on high trim level trucks in the early 70s. Many of the old times snorted at this candyass addition, but we forged ahead. It was on auto trans XLTs, the top trim level. It was so unsophisticated that at low speeds it caused a bucking bronco effect. Seems the vehicle sensor would detect a dip in set speed and the vehicle would go to Wide Open Throttle..OOPs...too much speed gain..so Closed throttle...OOPs...Too low...back to WOT...and so on.... Made it very limited as to when it actually worked as is should. Modern Cruise is so much better!

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

My last truck was an 88 Ranger. It bucked like crazy whenever I used cruise control. My wife forbid me from using it whenever she was riding with me.

 

[dmeyer302]

Many of the old timers snorted at this candyass addition, but we forged ahead.

Let’s be honest: you could be describing any new feature ever added to a truck in the last 100 years........evidently up to and including ACC!

A/C
Power windows
Heated seats
Tailgate damper
4x4
Auto transmission
Tailgate step
EFI
And on and on...

 

[CoastieN70]

OK, I just read this entire thread and have a couple thoughts here:
You might be right on the cusp of a gear shift at 34 MPG (thought 1)
Auto Stop/Start could be a factor, try disabling it (don't ask me why, it just popped into my head, thought 2)
Disable Adaptive Cruise and see what happens, if it solves your problem check your Adaptive Cruise/ collision alert sensor for obstruction (thought 3)

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