Clunky acceleration?

[kmarnes]

2017 Explorer Sport, 1000km on it today, almost all of it city driving.

I first noticed past weekend when wife drove, she pulled out to do a U-turn and I thought she was driving badly... was like she couldn't control the power and was hitting the gas and letting off, hitting the gas, letting off... etc, about 3 or 4 times in the space of the U-turn.

Since then I've experienced it on my own a couple times. It's really subtle, but only seems to do it when I first start up the car and pull out for one or two seconds, and then everything is fine.

Any ideas?

 

[BMan5150]

My 2014 sport also has an odd oscillating throttle when I first start the car. Been there since new, and goes away within the first 1 mile of driving. A little odd albeit, but we've not had any related issue with the vehicle. Others have noticed the same thing. I'd also characterize it as very subtle. My wife has never even noticed it...only me being a gear head! LOL,

 

[Odrapnew]

My 2014 sport also has an odd oscillating throttle when I first start the car. Been there since new, and goes away within the first 1 mile of driving. A little odd albeit, but we've not had any related issue with the vehicle. Others have noticed the same thing. I'd also characterize it as very subtle. My wife has never even noticed it...only me being a gear head! LOL,

Same here. I notice it when pulling out of a parking spot under very light throttle application. Usually gone within the first 10 seconds of driving for me.

 

[kmarnes]

Okay thanks for the responses. I feel a little better now, but it is a little odd. Anyone ever try to get this looked at? It's pretty minor, but it's almost like the car needs a moment to warm up before you drive off or something. Wonder what's really happening.

 

[Exit32]

The behavior you describe is called "surging" and it happens when the engine is warm, just restarted, and driven at low speed (partial throttle). It happens to my Explorer while I'm running errands. For example, if I stop, turn off the engine, run into a store, then return and pull out of the parking lot.

I believe this surging is an Ecoboost characteristic and has to do with a temporary build-up of condensation inside the air intake tube caused by an efficient Charge Air Cooler (CAC). Once the condensation is purged, everything returns to normal.

 

[kmarnes]

Okay I think that fits it well, when the car is already warmed up and you stop for a few minutes. Happened after picking up fast food, and another time after stopping at a bakery.

 

[peterk9]

Never noticed anything like that with mine in the 2 1/2 years I've had it. I'm guessing that the engines are identical.

 

[dentalpain]

As a fellow gearhead, I noticed this too on my 15 and 16 sports (worse on the 15). Damp humid morning was also a leading cause. My wife never noticed it. I did some reading and found cars start on a "closed loop" and read A/F data from a table during the first few mins, until its up to temp...then it goes open loop and reads data from sensor (like the O2s and MAF). It wont happen when in open loop. I had my tuner (torrie) look at data logs and we didn't find anything out of order.

/I probably got something wrong in there so research it on your own.

 

[Odrapnew]

The behavior you describe is called "surging" and it happens when the engine is warm, just restarted, and driven at low speed (partial throttle). It happens to my Explorer while I'm running errands. For example, if I stop, turn off the engine, run into a store, then return and pull out of the parking lot.

I believe this surging is an Ecoboost characteristic and has to do with a temporary build-up of condensation inside the air intake tube caused by an efficient Charge Air Cooler (CAC). Once the condensation is purged, everything returns to normal.

I should say, I'm not sure I've noticed it after a warm start, just cold starts and under very light throttle application. However, the times I notice it is when leaving work slowly driving through the parking lot. That's usually after my Ex has been sitting for 8-10 hrs.

As a fellow gearhead, I noticed this too on my 15 and 16 sports (worse on the 15). Damp humid morning was also a leading cause. My wife never noticed it. I did some reading and found cars start on a "closed loop" and read A/F data from a table during the first few mins, until its up to temp...then it goes open loop and reads data from sensor (like the O2s and MAF). It wont happen when in open loop. I had my tuner (torrie) look at data logs and we didn't find anything out of order.

/I probably got something wrong in there so research it on your own.

You have your open loop and closed loop backward.
Open loop is when it's cold or just started. The computer uses data in tables and functions to "make the engine run".
In closed loop, the computer looks at the feedback from various sensors to adjust parameters to make the engine run at peak performance(for a given condition).

 

[kmarnes]

I was able to repro it. This morning in Vancouver was a chilly morning, lots of condensation everywhere. I started the car up cold, no problems at all. Made a 20 minute stop for an appointment, and when I came back, I got the oscillating throttle while backing up on low throttle. Was barely an issue, possibly because the engine didn't have enough time to build up the internal condensation. I bet if I left it an hour first to give it more time to cool down, it would have been a bigger oscillation.

Like others have said, I never get this problem on a cold start. I only see it when I running errands and stopping here and there for a few minutes at a time. And it only lasts a couple seconds, but the duration and intensity varies based on how long the car sits between moving.

 

[twobanger]

I have a 16 and I notice that there is a sensation of what I remember as a broken motor mount on slight acceleration.

 

[974X4BLACKSPORT]

I have noticed my car do this too, but only very recently in the past 9 years I have owned it...strange thing is it;s a 2000 GTP.

 

[bigtexan99]

I get this as well in my 16 Sport. Its most noticeable if the car is started and then immediately driven in a slow speed turn. I never notice it again after the car has had a few minutes to run.

Tech at the dealer thought it might be the clutches binding on the AWD during the slow speed turn and once the car warms up the clutches no longer bind. We never were able to prove that, but that was his theory. I think the Tech thought that because I described the jerking as similiar to turning a 4wd (not AWD) vehicle in 4x4 Lo and how the front tires jerk. But I think a better description is how the OP described it in the first post....giving it gas, letting off, giving it gas, letting off.

As far as the condensation and the warm engine scenario that was described above, I would disagree. The symptoms for me usually occur on a cold start.

 

[cipher]

Just bought my 17 Limited. I thought I was imagining this but now I'm convinced it's really there. Slow speed going through a parking lot slightly above idle and/or when in a turn. Tried eying the tachometer to see what the RPMs are doing, but by the time I finish the turn safely and make sure I'm not going to mow some pedestrian down it seems to go away.

 

[613GT500]

As an FYI, during a road test by a Ford tech (after replacement of a failed PTU), a shuddering or surging was felt by the tech and it resulted in the replacement of the ETB and transmission.

 

[Benk016]

we have had our dealership look at our 15 Sport twice for a similar issue. Except ours usually manifests itself in the morning on a cold start, not at slow speeds, but when accelerating hard. Our neighborhood is right off the highway so we drive through the neighborhood fine, but when we pull onto the highway and go to accelerate to 70, it will hesitate pretty bad and surge a few times, and sometimes shift very strangely, and then about 10 seconds later it will be fine and drive fine the rest of the day. This happens maybe once a week and of course the dealership can never reproduce.

She also has the issue occasionally when its sat in her works parking garage for 8 hours, and starts and drives with little acceleration leaving the parking garage.