How do i know if the Injectors is bad?

2007 TOYOTA CAMRY
300,000 MILES • 2.4L • AUTOMATIC
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JOE1953
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How do i know if the Injectors is bad? misfire on #3 and #4 Cylinder. rough idling i replace coils and spark plugs.
Jun 30, 2026 at 6:17 AM
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STEVE W.
  • ✓ASE Certified Mechanic
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  • ASE Certified Mechanic
With misfires on two adjacent cylinders I would do a compression test before going any farther. Not uncommon for a head gasket to fail between two cylinders. The gasket is very narrow at that point and there are no coolant passages so a failure will show as both cylinders misfiring as the compression passes between them.
https://www.2carpros.com/articles/head-gasket-blown-test/
Will show you how to do the test. Doing a leak down test using compressed air would also show if it were the problem. You would put air into cylinder 4 with it on TDC and have air exiting cylinder 3.
Jun 30, 2026 at 8:11 PM
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