If your car stumbles, hesitates, or loses power at highway speeds, you’re not imagining things—and you’re not alone. An engine misfire at 65–75 mph can turn a normal commute into a white-knuckle drive and may signal a defect your manufacturer should fix under warranty. At ZapLemon, a California lemon law firm, we help consumers understand their rights when recurring misfires won’t go away despite multiple dealership visits. The information below is educational, not legal advice, and a consultation is needed to evaluate any particular situation.
Engine Misfire at Highway Speeds? Know Your Rights
Highway-speed misfires can feel like brief shudders, sudden drops in power, or the car slipping into “limp mode.” You might see a flashing or steady check engine light, smell fuel, or feel the vehicle surge and hesitate when merging or passing. Common root causes include failing ignition coils or spark plugs, clogged fuel injectors, weak fuel pumps, faulty crank or cam sensors, software glitches, or catalytic converter problems—issues that can compromise safety when you need steady power on the freeway.
If your vehicle is still under the manufacturer’s warranty and keeps misfiring, the dealer generally must be given a reasonable opportunity to diagnose and repair it. That means taking the car to an authorized dealership (not just an independent shop) so the manufacturer has the chance to fix the defect with factory procedures, parts, and software updates. Keep every work order and invoice, note your mileage, describe the misfire in your own words (for example, “shudders between 60–70 mph on uphill grades”), and ask the service advisor to include that language in the repair record.
A few practical tips go a long way. If the misfire happens intermittently, record a short video showing RPM fluctuations, warning lights, or the behavior under load; note the fuel level, outside temperature, and speed when it occurs. Ask the dealer to scan and list all diagnostic trouble codes (DTCs) on the work order. Check for open recalls or Technical Service Bulletins (TSBs) related to your engine or ECU software. If the problem returns, escalate by contacting the manufacturer’s customer care to obtain a case number—and bring the car back promptly so the pattern is documented.
How California Lemon Law Applies to Misfire Cases
California’s Song-Beverly Consumer Warranty Act—commonly called the California Lemon Law—may apply when a new or certified pre-owned vehicle under warranty has a defect that substantially impairs use, value, or safety, and the manufacturer (through its dealers) can’t fix it after a reasonable number of repair attempts. A persistent engine misfire at highway speeds often affects both safety and use, especially if the vehicle loses power during passing, struggles on grades, or regularly enters limp mode.
What counts as a “reasonable number” depends on the circumstances. California has a “lemon law presumption” that can apply within the first 18 months or 18,000 miles if certain thresholds are met (for example, multiple repair attempts or the vehicle being out of service for a specified number of days), but you can still qualify outside those benchmarks based on the overall repair history. Safety-related defects—like a misfire that causes stalling—may require fewer attempts than minor issues. The key is clear documentation: dated repair orders, mileage in and out, and consistent complaints noted on each visit.
If your vehicle meets the legal standards, potential remedies can include repurchase (often called a buyback) or replacement, subject to a mileage offset and other statutory rules. Some manufacturers offer informal dispute programs or arbitration, which can be optional or required depending on the terms in your warranty booklet. Because each case turns on specific facts—warranty coverage, timing, number of attempts, and how the misfire affects safety and use—speaking with a California lemon law firm like ZapLemon can help you understand your options before you make a decision.
Attorney Advertising. This article is for informational purposes only and is not legal advice. Reading it does not create an attorney-client relationship with ZapLemon. Outcomes depend on the facts of each case, and no guarantee is made. If you believe your vehicle may qualify as a lemon due to engine misfires at highway speeds, contact ZapLemon for a consultation at www.zaplemon.com. Keep your repair records handy, and we’ll review your situation to help you understand your rights under California law.