A car that cranks at normal speed and never catches has a different fault from one that clicks, drags or does nothing, and most writing on the subject runs the two together. This page is only the first half, fuel and spark, and for every number it says whether the source was a regulation, a manufacturer's own maintenance schedule, or somebody selling the part.
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Turn the key and listen to the first two seconds. If the starter drags, clicks once, clicks rapidly or does nothing at all, the fault is upstream of the engine: battery, starter, alternator, cables. That is a different repair and it has its own page here, why won't my car start.
This page is the other case. The starter turns the engine at normal speed, you can hear it spinning, and it never catches. The engine is being turned; it is not burning anything. There are only three ways that happens, and the regulator writes them out in a definition. California's OBD II regulation, which is the one federal law adopts, defines the fault this way: “Engine misfire” means lack of combustion in the cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause.
Spark, fuel, compression. Compression is a head gasket, a snapped timing belt or a burnt valve and is a workshop job from the first minute. Fuel and spark are the two an owner can narrow down, and they are what the rest of this page is about.
CARB's final regulation order for section 1968.2, section (c), definitions.
The car has been watching itself the whole time, and what it stores is more specific than anything you can work out from the driveway. 40 CFR 86.1806-17 says model year 2017 and later vehicles must have onboard diagnostic systems, and then does something unusual: instead of writing its own specification it adopts California's. Vehicles must comply with the 2013 OBD requirements adopted for California, meaning Title 13, section 1968.2 of the California Code of Regulations. So the rules below are California's text, binding on cars sold anywhere in the United States.
The data comes out of the connector in a standard format. The federal rule itself asks manufacturers to submit the SAE J1979 test results (e.g., Mode/Service $06), which is the standard any cheap code reader speaks. Pull the codes first. A cylinder number costs nothing and rules out half the page.
40 CFR 86.1806-17; CARB's final regulation order for section 1968.2, sections (e)(3) and (e)(6); SAE J1979.
On a modern car the pump sits inside the fuel tank. That they fail is not folklore: Toyota's recall 20V012, opened in January 2020 and twice expanded, covers 1,830,752 vehicles because the low-pressure fuel pump inside the fuel tank may fail, and Honda recalled 135,995 more that year for the same part, in the same sentence. Read the agency's wording closely, though, because it is about the crash risk rather than your driveway: if the fuel pump fails, the engine can stall while driving, increasing the risk of a crash. NHTSA describes the stall. The no-start is that failure found stationary.
A pressure test puts a gauge on the feed line and reads what the pump delivers with the engine running. Two things about the number, and both come from the manual for the tool rather than from anyone independent, because the people who publish this are the people selling the gauge. First, it is not one number: a port-injection test kit carries a 0–100 psi gauge, while the same manual warns DO NOT use this kit to test direct injected engine line pressure between the high pressure pump and injectors, as the high pressure (1500 to 3000 psi) will cause failure of the hoses and/or gauge, and tells the technician to read that side with a scan tool instead. Second, the pass mark is per engine: the same manual tells the technician to understand what the typical pressure is in the line you desire to test before connecting the gauge, rather than to compare against one number. Any page quoting a single figure for all cars has invented it.
Gasoline direct injection is why there are two pressures. fueleconomy.gov on engine technologies, run by Oak Ridge National Laboratory for the Department of Energy and the EPA, puts the difference plainly: in conventional engines fuel is injected into the intake port and mixed with air, while in direct injection systems fuel is injected directly into the cylinder. Toyota's own California emission warranty parts list for the 2024 RAV4 names a High-pressure fuel pump and Injector as covered parts, which tells you which system that car has.
One caution from the same tool manual, aimed straight at the most common home diagnosis: a noisy pump may not be an indication of poor operating condition. A whining pump is a reason to test, not a verdict.
NHTSA recall 20V012 and NHTSA recall 20V314; ATD Tools' fuel injection pressure tester manual; fueleconomy.gov on engine technologies; 2024 RAV4 Warranty & Maintenance Guide.
This is the single most useful thing this page can settle, and it is settled by counting words in documents the manufacturers publish.
Toyota's 2024 RAV4 Warranty & Maintenance Guide and its 2025 Corolla Warranty & Maintenance Guide do not contain the phrase fuel filter anywhere. Not in the maintenance chart, not in the warranty parts lists, not in the footnotes. What they do schedule around the fuel system is an inspection: Fuel Lines and Connections, Fuel Tank Band and Fuel Tank Vapor Vent System Hoses, and the fuel tank cap gasket. The 2009 Sequoia Scheduled Maintenance Guide is the same, and so is the 2001 Toyota Scheduled Maintenance Guide, so this is not a recent change.
Where a filter does survive, the schedule says so and says which engine. GM's 2016 Chevrolet Colorado maintenance schedule carries exactly one such line: Replace fuel filter. (2.8L 4 - Cylinder Engine). The EPA and DOE's own record for that engine, fueleconomy.gov on the 2016 Colorado 2WD, reads Diesel Vehicle 4 cyl, 2.8 L; the 2.5 and 3.6 gasoline engines in the same truck get no fuel filter line at all.
The federal maintenance rule files it the same way. 40 CFR 86.1834-01 splits scheduled maintenance into emission-related and not, and puts fuel filter change in the second list, next to oil changes and air filter changes — the ordinary-wear pile, not the emission parts whose intervals EPA polices.
Against that, AAA's tune-up page lists Replacement of fuel filter as a standard part of a tune-up, with its own explanation of why the filter clogs. AAA is a motor club rather than a parts seller, but it runs an approved-repair network that the same page sends you to. The practical rule: if your maintenance guide names a fuel filter, it has one and it is due at a stated mileage. If the guide never uses the words, ask the shop to point at the line in your schedule before paying for the job.
Ask who decides when spark plugs are due and the answer is not the plug maker and not the dealer. It is a federal regulation, and it sets a floor rather than a recommendation.
40 CFR 86.1834-01 governs what maintenance a manufacturer may schedule for emission-related parts, and paragraph (b)(1) ties it directly to your booklet: the durability schedule must use the same intervals that will be specified in the manufacturer's maintenance instructions furnished to the ultimate purchaser. Then it fixes the shortest intervals EPA will accept:
And the sentence that gives those numbers their weight: The Administrator has determined that emission-related maintenance at shorter intervals than those outlined in paragraphs (b)(3) and (4) of this section is not technologically necessary to ensure in-use compliance. A shop recommending plugs more often than every 30,000 miles is recommending something the EPA has already declined to call necessary.
What the makers actually publish is far longer than the floor. Toyota's 2024 RAV4 guide replaces the plugs once, at 120,000 miles or 144 months, and the 2009 Sequoia guide said the same. Go back to Toyota's 2001 guide and the schedule sits right on the federal floor: Replace non-platinum spark plugs at 30,000 miles, and again at 60,000 and 90,000, on the Sequoia, Tacoma, Tundra and 4Runner. Earlier in the same booklet Toyota is selling the alternative, and says Toyota's platinum and iridium plugs are designed to last at least 60,000 miles — a manufacturer's claim about its own part. The interval did not get more optimistic; the plug changed, and iridium is where the 120,000-mile figure comes from.
Coils are the other half and they are warranted differently. Toyota's federal emission control warranty parts list covers Ignition coil and ignitor, Ignition wires and Spark plugs*, with the asterisk reading Warranted until first required maintenance under terms of the applicable regulations — so plug coverage ends at its first scheduled change while the coil keeps the full emission-defect term. In California-standard states the RAV4's long-term list runs seven years or 70,000 miles and includes the high-pressure fuel pump and the injectors. Before paying for any of these parts, check which warranty you are still inside.
Whether your car has plug wires to inspect is answered by the same document. GM's 2016 Colorado schedule says Replace spark plugs and inspect spark plug wires; Toyota's RAV4 maintenance chart schedules plugs and no wires. And because the regulation requires the code to name the cylinder, the cheapest ignition test there is costs nothing: move the coil from the cylinder the code named onto another cylinder, clear the code, and see which cylinder the car names next.
One thing this page will not tell you is how to read a used plug by its color. Every chart for that traces back to a plug manufacturer, and nothing independent could be verified, so it is left out.
40 CFR 86.1834-01; 2024 RAV4 Warranty & Maintenance Guide; 2009 Sequoia Scheduled Maintenance Guide; 2001 Toyota Scheduled Maintenance Guide; 2016 Chevrolet Colorado maintenance schedule.
The clearest description of what a tune-up used to be is sitting in a rule that is still in force. 40 CFR 86.1834-01 lists the emission-related items a manufacturer may schedule, and the list reads like a 1975 workshop: spark plugs at 30,000 miles; at 50,000, Positive crankcase ventilation valve, Emission-related hoses and tubes, Ignition wires and Idle mixture; at 100,000, Carburetors. The non-emission list in the same section still contemplates lubrication of carburetor choke linkage and re-torquing carburetor mounting bolts. That was the tune-up: set the ignition, set the mixture, replace the parts that wore out doing it.
None of those adjustments exist on a car with an engine computer, and yet the word survives on invoices. Toyota's 2024 and 2025 warranty booklets list Engine tune-ups among the normal maintenance services the warranty does not cover, and never define it.
What a shop means by it now is an inspection package. AAA's tune-up page describes it as inspecting air filters, spark plugs, ignition wires, belts and hoses, suspension components, battery and charging system, fuel filter, fluid levels, exhaust, brakes, steering and tires, possibly with a throttle body and fuel system cleaning and a diagnostic scan. AAA also gives the interval: Older vehicles with non-electric ignition require yearly servicing or intervals of 10,000 to 12,000 miles, while newer vehicles with electric ignition need servicing every 25,000 to 100,000 miles. That is a 75,000-mile span, which is the honest measure of how little the word now means.
Price the line items separately, because at least one of them stopped working. fueleconomy.gov on keeping a vehicle in shape, run by Oak Ridge National Laboratory for the DOE and EPA, states that replacing a clogged air filter on vehicles with fuel-injected, computer-controlled gasoline engines — such as those manufactured from the early 1980s to the present — or diesel engines does not improve fuel economy, but it can improve acceleration, citing SAE technical papers from that laboratory. On a carbureted engine it improved both. The item stayed on the tune-up list after the reason for it left.
Start with what is already in the tank. 40 CFR 1090.260 requires that all gasoline sold for use in motor vehicles must be treated with a detergent meeting the rule, at least at that detergent's certified concentration. It is not a suggestion and it is not a brand feature; it is every gallon.
The test behind it is specific. Under one of the permitted methods in 40 CFR 1090.1395, a detergent maker runs a 100-hour intake valve deposit test on a base fuel that must accumulate at least 500 mg on average per intake valve, then repeats it with detergent added; if the result is less than 50 mg average per intake valve, that concentration certifies. So the legal floor is at least a tenfold reduction in valve deposits, measured on a test engine.
Now the two manufacturers, each of whom has something to sell. GM's Chevrolet Spark owner's manual says of additives: In most cases, nothing should have to be added to the fuel. It then notes that some gasolines carry only the EPA minimum, recommends TOP TIER fuel, and adds: For customers who do not use TOP TIER Detergent Gasoline regularly, one bottle of GM Fuel System Treatment PLUS, added to the fuel tank at every engine oil change, can help clean deposits from fuel injectors and intake valves. GM Fuel System Treatment PLUS is the only gasoline additive recommended by General Motors. It is available at your dealer. Toyota is narrower and stranger: the 2025 Corolla's maintenance chart schedules Add EFI Tank Additive, footnoted Toyota genuine fuel injector cleaner or equivalent, in Hawaii, Puerto Rico and Saipan only, and the 2024 RAV4's log schedules Add Toyota EFI Tank Additive or equivalent in those three and American Samoa. Everywhere else in the United States Toyota schedules no additive at all.
The nearest thing to independent evidence is AAA's 2016 fuel-quality release, and it is important to be clear about what it tested: gasoline, not a bottle. AAA reported that non-TOP TIER gasolines caused 19 times more engine deposits than TOP TIER brands after 4,000 miles of simulated driving. AAA paid for the work and, in its own words, engaged the services of an independent International Standards Organization 17025 certified engine testing lab to perform an ASTM International standard test on fuels; TOP TIER itself is an automaker-backed program. AAA's own conclusion for a rough-running car is a fuel change rather than a product: After a few thousand miles with TOP TIER gasoline, performance issues like rough idling or hesitation during acceleration can often be resolved.
What could not be found is a published independent test of a bottled injector cleaner. Every claim of the form “independent testing shows” that turned up for this page resolved to a retailer, a parts blog or a summary with no document behind it, so no figure for bottled cleaner appears above. And the federal rule already treats injectors as a 100,000-mile item, not a service interval.
The safe half is everything that does not open the fuel system. Pull the codes and write down the cylinder number. Confirm there is fuel in the tank — the tool manual's own pretest list says make sure fuel tank has sufficient fuel (do not rely on fuel gauge), because a failed sender reads a quarter tank forever. Check the fuses. Check the battery, because the same list notes a weak battery will not ensure proper pump delivery or injector triggering and should read over 12 volts. Look for a disconnected connector or an arcing ignition wire.
It stops at the fuel line, and the reason is in the relief procedure itself. Before a technician may put a gauge on, the manual says: do not smoke, wear safety glasses, keep a dry chemical Class B fire extinguisher near you, disable the fuel pump, run the engine until it stalls, then crank for three to five seconds. That whole sequence exists because the line still holds gasoline under pressure after the engine has stopped. Opening a fitting without doing it sprays fuel across a hot engine bay. On a direct-injection car the high-pressure side runs at 1,500 to 3,000 psi by the same manual's warning, and it tells even professionals to read that side with a scan tool rather than a gauge.
Then the arithmetic, which nobody selling the repair will do for you. A no-start is the worst possible position to sell or trade from, because the car cannot be driven and every buyer prices in the most expensive explanation. Before authorizing a diagnosis-then-parts sequence on an older car, get the repair estimate in writing against what the car is worth running, and check the emission warranty first, in your own booklet: the 2024 RAV4's California long-term list names the high-pressure fuel pump and the injector and runs seven years or 70,000 miles, and the federal defect warranty covers the list printed in the same booklet. A part that failed inside its term is not your bill. Our pages on fix it or junk it and when to stop repairing a car run that comparison.
If the number comes back higher than the car is worth, stop. Each guess at a part adds its own cost to the bill whether or not it was the fault, and a car sold as a non-runner is at least sold with the fault described rather than guessed at.
Fuel, spark or compression. California's OBD II regulation, which federal law adopts for cars sold nationwide, defines engine misfire as lack of combustion due to absence of spark, poor fuel metering, poor compression, or any other cause. If the starter drags, clicks or does nothing instead, the fault is battery, starter or alternator and that is a different repair.
Usually not. Toyota's 2024 RAV4 and 2025 Corolla maintenance guides never use the words fuel filter at all, and the 2016 Chevrolet Colorado schedules one only on the 2.8-liter engine, which the EPA and DOE's fueleconomy.gov record lists as a diesel. Federal rules classify a fuel filter change as non-emission-related maintenance, alongside oil and air filters. If your own guide never names one, ask the shop to point at the line before paying.
Federal regulation sets the floor: 40 CFR 86.1834-01 says light-duty spark plug replacement occurs at 30,000 miles and at 30,000-mile intervals thereafter, and that anything shorter is not technologically necessary. What manufacturers actually publish is far longer. Toyota's 2024 RAV4 guide replaces them once, at 120,000 miles or 144 months.
Misfire severe enough to damage the catalytic converter. The OBD regulation requires that on detection of catalyst-damaging misfire the light shall blink once per second at all times while misfire is occurring. A steady light is a stored fault; a blinking one is damage happening now, and the car should be stopped.
No independent published test of a bottled injector cleaner could be verified for this page. What is established is that federal rules already require every gallon of US gasoline to carry a certified detergent, that GM's own manual says in most cases nothing should have to be added to the fuel before recommending the bottle it sells, that Toyota schedules an additive only in Hawaii, Puerto Rico, Saipan and American Samoa, and that AAA's own testing was of detergent gasoline rather than of any bottle.