Hi all,

I've been googling for an hour and can't figure out what is wrong with my 2012 5.0 f150. The issue started literally the second or third gas fill-up I did since buying it brand new off the lot. Here's the deal:

Turn engine on. Shift into gear. Accelerate. There's a 50% chance it starts to lunge forward rhythmically. Like every second it lunges, then pulls back, then lunges, then pulls back, etc. If I keep holding the gas down and let it keep lunging, it gets worse and *almost* sounds like mechanically something underneath or under the hood of the car is stressing out and making knocking or clicking noises. At that point I just let off the gas because I'm afraid of breaking something, then let the truck take a few seconds of recovery, and hit the gas again and take off.

The other way I can get through the lunges is hit the gas hard and not let the truck get into that rhythm. Although this option doesn't really work in parking lots and places like that because, well, its unsafe.

When the truck lunges forward for that second, it coincides with a rev in RPMs from what I can tell. It seems like it happens more-so when I am going uphill, but that could be simply because you have to gas to get up the hill, vs coasting down a hill. I have not noticed this issue without hitting the gas.

I plan on taking it into the dealership before my warranty expires so they can check it out, but I assume they will say "Cannot reproduce" because the odds of it happening are like 50%. It takes about 30 mins or so after the truck is turned off when it can happen. I usually can't reproduce it if I am turning off/turning on the truck in short durations. So if I had to make a guess, it has to do with the engine being "cold" after the cool down.

One thing I noticed is the brand of gasoline seems to affect the severity of the lunges. Shell being a bad one and Sheetz or Murphy a little better.

Since this issue appeared right away within a few weeks of pulling off the new car lot, I can't imagine it being dirty fuel injector, lines, bad spark plugs, etc. But maybe it is? I looked through the recalls and nothing, although I did notice other truck users having lunging issues but my issue seems a little different. Once that initial 30 seconds goes by the truck operates normally.

Any ideas? I'd like to try to narrow down the possibilities so when I bring in the truck, the technician has a starting point to go from. Thanks!

PS - It occurred to me that I might be able to capture it on video and I will give that a shot.

 

I have a 2012 FX4 and from what you are describing is a lot like the way mine acts when cold. How ever mine does not do it nearly as frequently as yours.

I have talked to my locale dealer and they had it for 3 days and it never did it because it is so intermittent on mine

Have you found out any more on this?

 

My '12 Lariat 5.0 did this too. Usually as i was leaving my driveway or leaving work. Though it only happened 1 out of 10 times. I would just let off gas and then start again and it would be fine.

I believe somewhere on here there is a TSB on this or maybe it was an alternative solution.

My mom has a '14 Lincoln Navigator and hers does it also from time to time.

 

Here you go. https://www.f150forum.com/f38/ford-s...needed-274349/

https://www.f150forum.com/f38/new-tr...n-cold-170691/

 

My dealer decided to update/flash the power control module (I believe it is what they called it). It's been about 3 months or so and the problem appears to have gone away with the severe lunging. But, there still is an idling problem and gear switching, something others have noticed as well. It's not as problematic so I haven't taken it in yet. I'm conflicted really, because I love the truck but don't want something catastrophic to happen after the warranty ends. A guy at work has the same year as mine but the ecoboost engine and he has zero issues.

 

Hi f150#1,

I reached out to you on another forum, but I wanted to make sure I touched base with you here, too. Are there circumstances under which you can make this happen? If so, consider taking your tech on a test drive so you can replicate it for them. How many miles are on your truck? I'll research some ways to help.

Let me know if you decide to head back in to the dealership, stevedave. What's the current mileage on your rig?

Crystal

 

About 25-26k miles. I might head back next week but it will be problematic if they want the truck for more than a day since I work. Just curious Crystal, who are you and do you work in corporate HQ or something? Thanks!

 

I have been doing the same.

 

It is so intermittent that I am unable to make it do it. The other thing is it’s not a cold weather thing either because it will do it during the summer if it has sat for a while. I have just got use to having to let it run for a bit before I put it into gear.

 

Having your dealership take a look at the truck is a great first step toward resolution, stevedave, but I do understand where you're coming from. I suggest using this tool to schedule an upcoming appointment, and also to reach out to them regarding any options they may have. If you explain your situation, they may have some resources available.

To answer your other question, Crystal is a customer service representative on certain designated forums, just like me. I was out of the office yesterday and she jumped in to cover.

Please let me know how things go moving forward, and what the dealer says when you have the chance to contact them. I'll be here and ready to assist.

I hear you, f150#1. When you're comfortable and ready to do so, feel free to use the tool provided above to get that appointment scheduled, and please let me know how things unfold. I'll be keeping an eye out for any updates.

Brittany