Engine Misfire Repair in San Mateo, CA
Flashing CEL? Rough idle? Hesitation under load? Cylinder isolated, cause identified — spark, fuel, or compression — before any parts get quoted. From $99 diagnostic.
An engine misfire is one cylinder not contributing — and the rest of the engine has to work harder to compensate. Rough idle, hesitation, shake at stoplights, fuel economy crashing. Beacon Auto Care in San Mateo isolates the misfiring cylinder, then tests the components on it (plug, coil, injector, valve) until we know what's actually wrong.
Real Customer Finding
From a 2009 Toyota Tacoma inspection at 142k miles: "Spark plugs extremely worn out, contaminated with engine oil." Photo of the plugs went to the customer's phone. Diagnosis: valve cover gasket leaking onto the plugs + plugs at end-of-life. Fix: gasket + plug job. CEL cleared, idle smoothed out.
Diagnostic Sequence
- OBD-II scan + freeze frame — identifies which cylinder (P030X codes)
- Coil swap test — moves coil to next cylinder, see if misfire follows
- Plug inspection — fouling, gap, wear pattern, oil contamination
- Compression test — rules out mechanical (valve, ring) failure
- Injector flow test — if compression and ignition test fine
- Cylinder isolated before any parts get quoted
- OEM-equivalent or genuine OEM plugs and coils
- Photos of plug condition + fault data sent to your phone
- 24-month / 24,000-mile warranty on parts and labor
Common Questions About Engine Misfires
What it feels like, what causes it, how we diagnose.
What does an engine misfire feel like?
Is a flashing check engine light from a misfire dangerous?
What causes misfires?
How do you actually find which cylinder is misfiring?
How much does engine misfire repair cost in San Mateo?
Related car symptoms
Other symptom? Tap below — or walk through our triage tool .
What San Mateo Drivers Say About Engine Repair
“I had a great experience with this shop. My car was consistently overheating, and I was worried about potential engine damage. They thoroughly inspected it, confirmed the radiator…”
— Asmaa A.
Read more“Fixed an electronic issue for $250 that Toyota said would require a full replacement for $3,000. Great service and great prices.”
— Leeza K.
“I needed a very quick diagnosis and exhaust fix with my registration renewal and smog test deadline one business day ahead. Flavio and Mo rose to the occasion and took a genuine…”
— Rocky K.
Read more“Brought my BMW here after 3 other shops diagnose it and failed to fix it or even figure out the problem and Moe was a great help he figured out the issue in no time and fixed it…”
— The King O.
Read more“I highly recommend! I was in the area for a day trip when I noticed my engine light was on. Most car repair shops were closed because it was Saturday afternoon. Luckily, Beacon…”
— Rhonda B.
Read more“I don't like leaving reviews, but this place deserves it. My check engine light was on for two years, and every place I went to always told me that they didn't know what was going…”
— Joon K.
Read moreRough Idle? Flashing CEL? Don't Wait.
Real cylinder-level diagnosis. Plain-English explanation. 24-month warranty on the fix.