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Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5449
Experience:  Auto Trans, Drivability and Electrical Specialist
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1999 Ford Ranger: 3.0 V6..Manual Trans, A/C..miss firing..coil pack

Resolved Question:

1999 Ford Ranger, 3.0 V6 Flex Fuel, Manual Trans, A/C,

Engine missing, code from O'Reillys says miss firing on #6 cylinder

Changed plugs, wires, and coil pack, no change. . .could this possibly be a valve problem?

Out of ideas
Submitted: 6 years ago.
Category: Ford
Expert:  Kenny Z. replied 6 years ago.
Hello and thanks for your question.

It very well could be I have replaced cylinder heads on many 3.0L engines for valve seat recession. Usually a compression test will confirm it if its bad enough. A cylinder leakdown test can also confirm it. They can be tricky to diagnose when the problem is first starting because as the valve rotates some times it will seal better then others as its opening and closing making it difficult to verify with compression or bleed down testing.
I would also verify the injector is firing correctly for that cylinder.
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