Misfire or rough idle on the 1998 Buick Lesabre
Only 4 reports for this mode came with an odometer reading, which is too few for percentiles to mean anything. The page is here because someone linked to it; treat the figures as anecdotes, and see the full report for this year instead.
When misfire or rough idle gets reported
There are 9 reports of misfire or rough idle on the 1998 Buick Lesabre, 4 with a mileage attached. That is too few to place the failure on the odometer with any confidence.
A part like this is normally expected to survive 92,000 miles. It is the 14th most-reported problem on this model year.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| — | — | 157,939 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
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 3 model years of this car. It shows up earliest on the 2000, at a median of 75,000 miles, and latest on the 1998 at 160,000 miles.
By volume the 1998 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.
First we would like to report our dissatisfaction with stillwater motors in that they added bogus charges on to the invoice then later, after we questioned and insisted on seeing these new parts and the old parts, they adjusted the invoice by crediting us $400. The car was brought in due to the engine running rough, overheating and an increased usage of coolant. The dealership diagnosed the problem as being a defect in the upper manifold resulting in leakage of coolant onto the sparkplugs. In the end, the upper manifold, 4 gaskets, the oil filter, and thermostat had been replaced and had the fuel/emission system flushed. We were quite astounded to see so many issues with this very same problem we had and we are hoping that there is some relief given to all buick lesabre owners who have had to incur these repair costs. *ph
While driving service engine light came on. Then, vehicle decelerated followed by heat and ventilation failures. This was due to engine intake manifold malfunctioning. The manifold wasn't designed correctly by the factory engineer, which caused the engine to misfire. Dealership diagnostic test showed coolant leaking. Cylinder replaced, and lower intake manifold improved design, per bulletin 010601007a. Also, coolant and fluid plugs were replaced.*ak *nm
Also reported on the 1998 Buick Lesabre
Other engine problem
Other fuel system problem
Exhaust leak or fumes in the cabin
Other electrical problem
Radiator or coolant leak
No-start or intermittent start failure
How far this goes
This page is kept out of search results because 9 reports is not enough to publish percentiles from. It stays reachable because somebody looking at this exact car would rather see the reports than be told there are none.
Complaints are voluntary, so 9 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 1998 Buick Lesabre?
Across 4 owner reports that included an odometer reading, half were filed by 160,000 miles. A quarter were filed before — and a quarter after —. 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 1998 Buick Lesabre?
9 reports have been filed with NHTSA, about 0.1 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