Do spark plug replacement problems track gallons of motor gasoline burned per resident per year across states?
A weak hint, not a firm finding: across U.S. states, NHTSA owner complaints about spark plug replacement run higher where gallons of motor gasoline burned per resident per year is higher, after adjusting for the makes sold in each state. This is an association across states, not proof that gallons of motor gasoline burned per resident per year causes this repair.
State reports of this repair against gallons of motor gasoline burned per resident per year, one dot per stateEach dot is a state: how much more (or less) than expected this repair is reported there, adjusted for the makes sold in the state, against its gallons of motor gasoline burned per resident per year (SEDS, transportation)
How to read it: Each dot is a state. Further right means more gallons of motor gasoline burned per resident per year (seds, transportation); higher up means more complaints for this repair than expected (1.0 is average). If the dots climb to the right, reports of this repair rise with gallons of motor gasoline burned per resident per year (seds, transportation).
What it shows: States with more gallons of motor gasoline burned per resident per year (seds, transportation) tend to sit higher on the chart across 41 states: a pattern in the data, not proof of cause.
Data: EIA State Energy Data System, motor gasoline consumption, joined to NHTSA owner complaints, downloaded 2026-10-06 · 41 states. Chart: CalcScrape · calcscrape.com
The 10 states with the most gallons of motor gasoline burned per resident per year (Alabama, Mississippi, South Carolina, Missouri, New Hampshire, Arkansas, Kentucky, Tennessee, Texas, Delaware): reports of this repair run 5% above what the makes sold there would predict, and 7 of 10 are above expected. The 10 with the least (New York, California, Washington, Illinois, Oregon, Rhode Island, Pennsylvania, Massachusetts, Nevada, Maryland): 3% below, and 3 of 10 are above expected.
Exceptions: South Carolina, New Hampshire and Texas are among the highest in gallons of motor gasoline burned per resident per year but report below expected; Rhode Island (83% above expected) is among the lowest but above expected.
Split the states into thirds: the third with the least gallons of motor gasoline burned per resident per year runs 5% below what the makes sold there would predict, the middle third 7% above, and the third with the most 9% above. Most of the gallons of motor gasoline burned per resident per year effect sits between the lowest and the middle third.
For gallons of motor gasoline burned per resident per year, after allowing for the 1562 comparisons we ran, luck alone would produce a pattern this strong about 1 time in 5. The gallons of motor gasoline burned per resident per year pattern leans on New York: without it, it weakens.
Weak spot: compare only states with similar workers who drive alone to work and the pattern keeps about 0% of its strength, so part of it may come from workers who drive alone to work instead of gallons of motor gasoline burned per resident per year.
For gallons of motor gasoline burned per resident per year, of the 5 exception states, 2 read the same way for the other parts of the system (so that is the system there, not this repair) and 3 are specific to this repair.
Where residents burn more gasoline they drive more miles, and brakes, tires, belts and suspension wear out with miles.