Misfire or rough idle on the 1999 Ford F-350 SD
2 fires 2 of the 13 reports for this failure mention a crash, a fire, an injury or a death. Those are the owner's words on the complaint form, not a verified finding, and one report can mention more than one.
When misfire or rough idle gets reported
Owners of the 1999 Ford F-350 SD report misfire or rough idle at a median of 90,000 miles. A quarter of the reports come in before 70,000 miles and a quarter after 110,000 miles, from 11 reports that carried an odometer reading.
A part like this is normally expected to survive 92,000 miles. It is the 2nd most-reported problem on this model year.
The mileage distribution
The reported range runs from 60,000 miles at the tenth percentile to 120,000 miles at the ninetieth, a spread of 58,963 miles across the middle 80% of reports.
Reports bunched into a band this tight usually mean the component has a life of its own: it goes at roughly the same mileage regardless of who owns it.
0% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 61,037 miles | 67,893 miles | 91,660 miles | 107,687 miles | 120,000 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Of these reports, 2 a fire is mentioned. Owners write their own complaints and the agency does not verify them, so read this as what the reports say happened rather than as a confirmed count.
Putting it right typically runs $250–$1,600 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 5 model years of this car. It shows up earliest on the 2001, at a median of 65,000 miles, and latest on the 1999 at 90,000 miles.
By volume the 1999 is the worst of them, which makes this a problem of this specific year rather than of the model as a whole.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
April 2nd of 2004 driving at 30 MPH and coasting to a stop sign the number 3 spark plug blew out of the right side cylinder head of my 1999 ford f-350 with a v-10 engine in it. Ford in kingman,az. Installed a reconditioned cylinder head that had a spark plug blow out of it and a steel insert was the fix for that cylinder head. I was given a reconditioned head with the insert in it and told by the ford mechanic in kingman,az. That it is just a matter of time before it blows another spark plug out or sucks the steel insert into the engine. I sinserly hope I'm not 100 miles from anywhere when this happens again. I also hope it's not going to happen on the way to the hospital trying to help someone. This is a vast problem and can easily be researched on the internet by simply typing in "ford v-10 ,spark plug". Ford knows this is a casting problem with the aluminum heads having only 3 thread count in each cylinder hole holding each spark plug in. *ak
Truck has 56k miles on it. My wife was driving a couple of miles from hom ewhen she heard a loud bang or pop noise which shook the truck. The truck then continued making a loud noise, she drove back home and after looking at the engine, I determined that a coil pack had blown off. The spark plug was also attached to it so the next morning I called my local ford dealer, av ford and they said more than likely it's what they call a 'blown plug'. They estimated the head should be replaced since this would strip the threads of the head. The service advisor said this is a common problem and that both heads should be replaced at a cost of $5800 because otherwise I might have the same problem again in a short amount of time. I did some research online and found that this problem is very common with the ford v10 engines from about 1999-2003. I talked to a couple of other ford service techs at other dealerships and they agreed that it's a very common problem that ford is not recognizing or doing anything about. I called ford consumer relations to complain about the defect and they said before they can help me, I need to have the dealer…
Dt: the contact stated a spark plug ejected from her husband's vehicle. The spark plug caused damage to the engine and blew the cylinder head. The service dealer confirmed it. The dealer replaced the cylinder head. The replacement corrected the problem. The contact said this was the same problem as experienced in the investigation for the engine and engine cooling, NHTSA action number dp05005. *ak
Also reported on the 1999 Ford F-350 SD
Other wheel or tire problem
Other engine problem
Parking brake failure
Loss of braking
Steering rack, gear or tie rod failure
Tire blowout or tread separation
How far this goes
Complaints are voluntary, so 13 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does misfire or rough idle happen on the 1999 Ford F-350 SD?
Across 11 owner reports that included an odometer reading, half were filed by 90,000 miles. A quarter were filed before 70,000 miles and a quarter after 110,000 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is misfire or rough idle on the 1999 Ford F-350 SD?
13 reports have been filed with NHTSA, about 0.3 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed