misfires mystery

2004 LAND ROVER FREELANDER
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LOOKING4HELP
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Engine Performance problem 6 cyl All Wheel Drive Automatic 165000 miles

when taken into a shop for diagnostics the read out is pistons 2, 4, & 6 are misfiring. when driving the rpms are high and there is a loss of power going up hills. we replaced most of the air system besides the catalytic converter. and the car runs better when you unplug the sensors.
Aug 5, 2010 at 5:46 PM
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STRAILER
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Hello,

this is a classic problem with the MAP sensor. What happens is the sensor becomes contaminated which hinders its ability to read correctly. Here is a diagram (below) that will show you what you are in for when replacing this sensor along with the guide on general misfires.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please let us know what you find.

Cheers, Ken
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Jul 19, 2017 at 3:17 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.