Bad fuel injector symptoms
Clogged or worn injectors usually show up as a misfire, a rough idle or a lean code. Here's what to look for and how to fix it without guessing.
Common symptoms
- Misfire codes, often on one cylinder
- Rough or shaky idle
- Lean codes on one bank
- Hesitation or stumble under load
- Hard starting or a raw fuel smell
- Worse fuel mileage than usual
What causes it
Deposits build up on the injector tip and filter over time, especially after long storage or with poor fuel. The injector then flows less fuel or sprays unevenly, and that cylinder runs lean.
How to know for sure
A misfire can also be a coil, plug or vacuum leak. Testing the injectors off the car is the only way to see each one's actual flow. Our report shows every injector's numbers before and after cleaning.
Find out for sure: we flow test every injector and show you the numbers.
- Price confirmed before you ship
- Every injector numbered and tracked
- Tracked return shipping
- 90-day workmanship warranty
Common questions
Can one bad injector cause a misfire?
Yes. A single clogged or leaking injector is a common cause of a one-cylinder misfire.
Should I replace all injectors or clean them?
Clean and test them first. Most come back to spec; any that fail testing are flagged so you only replace what's bad.
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