Dozens of incidents of misfire and loss of power upon acceleration sometimes resulting in severe shaking and flashing of engine light. Has nearly caused accident on 2 occasions where I was unable to maneuver through traffic. In shop 3 times, first 2 times technicians supposedly could not replicate problem (very easy to replicate if trying to do it). Most recently advised that I might need a "tune-up" and oil change. 2 different service centers refuse to acknowledge a known problem despite a flood of postings on internet forums describing the exact same issue.

- Waxahachie, TX, USA

The contact owns a 2011 Ford F-150. The contact stated while driving various speeds there was a reduction in the engine power with an illumination of the warning indicator. The vehicle failed to accelerate over 30 mph. The failure recurred repeatedly over time. The vehicle was taken to an authorized dealer numerous times; however, they were unable to duplicate or remedy the failure. The manufacturer was notified of the defect. The approximate failure mileage was 29,000.

- Estacata, OR, USA

Truck frequently goes into limp mode/stalls. This has happened at various speeds, times, terrain, etc all over the country both with and without our camper attached and both with and without tow-haul engaged. I've taken it to the dealer numerous times and each time they've updated the software according to some tsb that's been released. I've had the deflector put on, cam changed, and now they're replacing the throttle body.

- Livonia, MI, USA

Engine misses at times of hard acceleration. Engine ecoboost.

- Gravette, AR, USA

Attempted to pass a car. Speed at time of attempt was 55mph. Time 2:20 P.M. and partly cloudy. Two lane road but had plenty of time to pass or an accident could have occurred. Pushed down on accelerator and the engine actually decreased speed/significant deceleration. I let up on gas pedal, maintained speed then was gradually able to pass. Think the turbo had stalled. This had happened once before, shortly after I purchased the truck. At that time I was merging onto interstate and it stalled out, for a shorter duration. After the July 31 incident, I took the truck to Ford to inquire about the issues some owners have had on the eco boast engine, which I have. No codes appeared so I was told they couldn't do anything. Then talked to regional customer service and got the same story. I am very concerned as I use the truck to tow a 26' trailer. When the eco boast turbo works, I have plenty of power to merge or pass. The above experience was scary and I did not have the trailer behind me at the time. Now I feel I can not reasonably depend on it to work as it should. I think it is the turbo but it could be the electronic gas pedal, or the transmission but I really do not think these are the issue. Please help! thank you.

- Kalamazoo, MI, USA

While accelerating to 75mph or so, up slight hill from 65-70 mph went to pass a vehicle then truck lost vast majority of power even with all the way down and began to violently shake. Could have easily cause accident since wasn't abble to accelerate as planned to match speed of other lane. Check engine light came on. Truck continued to shake violently off and on for next mile before stopping. Problem is still ongoing under any moderate acceleration that goes over ~2000 RPM

- Lake Forest, CA, USA

On several occasions and more frequently as of lately, I am losing acceleration capability when I am trying to accelerate at any speed. When I try to accelerate from a stop or uphill, I feel like the engine won't go or is bogging down. To try and compensate, I try to accelerate more which only seems to make the problem worse. I have already taken it to the Ford dealer and they replaced a part on the transmission, but the problem still persists and is only get more frequent.

- Prescott, AZ, USA

Was on the interstate just West of St. Louis, driving at 70 mph. Was a damp rainy day. Pulled in to the passing lane to pass a semi and truck lost power, went into "limp mode" with check engine light on. I pulled back into my lane and then off to the shoulder. Turned the truck off and sat for 5 - 10 minutes. When I powered it back up, the check engine light was off. I was able to pull back onto the highway and had full power for the rest of my trip. This is the third time this problem has occurred with this truck. Both other incidents were in damp or rainy weather at highway speeds when passing or merging onto highway.

- Sun Prairie, WI, USA

Had a car pull into my lane, tried to accelerate to move over with out causing a dangerousness situation of a car coming up in the lane I needed to be in to avoid the idiot moving into my lane but car lost power. Thankfully the car in the next lane over saw the issues with the car moving over into me and gave me room, I'm sure they didn't expect my car to slowdown due to the loss of power. This car has the ecoboost engine 3.7 liter

- Palm Beach Gardens, FL, USA

I was driving to Florida in my 2011 F150 ecoboost and on the highway at about 65 mph my truck started stalling and lost power miss firing and would not go over 10 mph causing me to pull over on the shoulder. I then turned the truck off and back on 10 mins later and it began to run fine agian. I took it to Ford and they say no engine codes went off so they did not know why it would do that.

- Phenix City, AL, USA

On August 11 2013, after about 2hrs of driving my 2011 Ford F150 with the ecoboost engine at a constant 72 mph I was coming out of a toll booth when the truck started to shudder and lose power this happened for about a minute, the truck regained power and continued.coming home on August 18th, again after alittle over 2 hours of driving, I went to pass slower traffic when the heavy shake, stutter and power loss happen.traffic behind almost ran me over.the stuttering/loss of power continued for about 3mins, in which I could not get to the side of the road and almost got my wife and I rear ended.Ford Motor Company has had many tsb for a possible fix on the 3.5L ecoboost engine but they have not worked.please help us before someone get killed.

- Ashford, CT, USA

Issue started again on 10 Aug. 2013. When under mild to heavy acceleration (such as merging onto interstates) the engine develops a significant miss and shudder. Vehicle was repaired once on 20 Mar. 2013 under tsb # 13-3-3. weather does not appear to be a factor. The "miss" was so severe with a K&N air charger high-flow intake kit installed that I had to reinstall the stock system. This was a none issue eventually because the Ford dealership would not place the vehicle on diagnostics until I had reinstalled the stock kit.

- Laurinburg, NC, USA

On I-20 East headed to augusta, ga from Alabama I pulled into the left lane to pass and the engine starts sputtering, skipping and lost almost all power. It happened 3 times yesterday. It was in a light rain and since there was light traffic I was able to slow down and get the engine to recover each time. This could be a real danger in heavy traffic. I tested it again this morning (08/18) and if you try to accelerate quickly it just about shuts down until you let off.

- North Augusta, SC, USA

The contact owns a 2011 Ford F-150. The contact stated that while driving at various speeds, the vehicle suddenly lost acceleration power. The contact also stated that the failure recurred intermittently. The vehicle was taken to multiple dealers where the failure could not be replicated. The vehicle was not repaired. The manufacturer was contacted about the failure. The failure mileage was 85,000. The VIN was not available.

- Madison, WI, USA

Well I have an issue with my trucks I have purchased from Ford. Well in August of 2011 I purchased the new F150 with ecoboost. The truck drove like a dream for a while then I started having issue, with the transmission, then engine losing power. This happen about 4 time during the life of the truck.the last time was in January 2013, it was the last straw for me. The reprogrammed the trans/computer and put a wind deflector in the front of the intercool. Still lost power on a road trip on the way back home from S Carolina. Mind you the truck was in the shop for tran/engine/the right fender had to be adjusted it was misaligned, the bed of the truck same thing. This lost of power almost caused me to have a accident because I was merging onto the highway. I also had to sunroof replaced as it was vibrating the whole truck when moving. The driver seat track was replaced and the sliding glass window in the back was replaced too. The defrost stopped then the window stopped sliding. I stopped driving the truck so I could get rid of it I have a 2013 limited and have some of the same issue. Now that I have a new 2013 vehicle I experience some of the same issue.

- Lithonia , GA, USA

Loss of significant power under slight to moderate acceleration, engine shutters violently, shakes and miss-fires. Check engine light flashes. Engine seems to run on 50% power loss, letting off accelerator for awhile then engine seems to recover temporarily until additional power is needed. Unable to have any confidence to pass any vehicles on grades. Quite possible for complete power loss under full acceleration as the engine misses so bad that it actually slows down and looses RPM's. I have owned this truck since new. Symptoms started in dry climate, no rain and have continued to get worse as I have entered into rainy areas with humidity.

- Scottsdale, AZ, USA

Went on a 350 mile trip, I was at a stop light and when I went to accelerate the truck lost all power. I have one of the ecoboost engines. The engine did fix itself and I continued with no other problem, this is the first time I experienced this problem. 2011 Ford F150 king ranch.

- Charlotte Hall, MD, USA

Second occurrence of the engine losing power while towing a camper over 100+ miles at highway speeds then adding power to climb a hill. Driving 65 mph on the highway, over a 1.5-2 hrs drive, approaching a hill while towing a camper, accelerated to climb the hill and the vehicle again, dropped from 65 to 40 mph in about 30 seconds. Engine stuttered and would not respond to throttle control to gain speed to climb the hill. Took vehicle into dealership no problem found, about a week later, there was an inefficient catalytic requiring the replacement of the left catalytic converter. This occurred post having the ecoboost fix that Ford Motor Company stated would resolve the problem and it is still occurring. Odbc 2 data logger captured the incident recording engine speed, engine RPM, and engine load (%).

- Rochester Hills, MI, USA

Ecoboost engine. Loud clattering on cold start. Runs very rough, exhibits propensity to stall when idling, and very sluggish acceleration coupled with transmission issues. Example 1: coasting on the freeway with traffic around 40mph, shifted lanes, then made attempt to accelerate and pass another vehicle, but the vehicle did not downshift. Accelerator will be down to the floor, and truck will remain stuck in a low gear (like 6th) and go nowhere...zero acceleration...after a few more tries, and a few seconds later, the transmission will slam into 2nd gear, shaking the entire truck. At this point, the turbos kick in and the truck takes off like a rocket. Creates 2 dangerous situations, a potential rear-end accident by the lane change without acceleration, and then the sudden, rapid, unpredictable acceleration of being randomly thrown into 2nd gear. Seen various other incidents like this in other scenarios and various gears. Accelerating out of a traffic circle, or out of a turn, is an easy way to see the problem. Truck has basically lost its ability to accelerate/downshift on demand. Example 2: stopped at a stop sign. When I then proceed into intersection...acceleration is very slow, then all of a sudden turbos kick in resulting in rapid unpredictable acceleration. Often times, the wheels will spin, and if the road is dry, the truck will bounce up and down all over the road! accelerator will in the same position the entire time. I have rapidly accelerated towards cars that I didn't want to get that close to. I now have to stay even further away from cars to maintain a safe distance due to unpredictable acceleration. Frustrating, because the problem is frequent now, but inconsistent. I have 2 kids in booster seats, and now I have to be especially careful when I drive with them in this truck because I feel it's unsafe.

- Macomb, MI, USA

This is on the ecoboost F150. I was driving during a rain and had been around 70 miles. The weather was rainy. I went to pass a farm tractor on a 2 lane road and the vehicle stuttered and had no power to pass. I had to take evasive action and get back into my lane where there vehicle continued to sputter for approximately another 2 minutes. I took truck to Ford and they replaced a converter and cooler. Last Wednesday under similar conditions, the same thing happened again on a vacation trip. Oncoming traffic had to evade me as I tried to get back into my lane. It has been less than 10, 000 miles since last attempted repair was performed by dealer. Obviously the repair did not work and now I am left with a vehicle with an obvious design defect that Ford doesn't know how to correct. Under different circumstances, this could be a serious safety issue.

- Alabaster, AL, USA