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2001 Jeep Wrangler I-6 Sensor Problem

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2001 Jeep Wrangler I-6 Sensor Problem

Truck Trend Truck Trend
Administrator | Posts: 4666 | Joined: 02/07
Posted: 01/16/09
03:42 PM

Question: I own a 2001 Jeep Wrangler I-6. I haven't had many problems with it until last year. The "check engine" light came on and the dealership confirmed it was the oxygen sensor. The techs told me it wasn't serious and wouldn't leave me stranded, but about two weeks ago the "check engine" light started blinking. The engine vibrated, seemed to misfire, and was slow to respond when I accelerated hard. The strange thing about this is it only happens sporadically. I changed the spark plugs and boots last weekend. My friend ran a diagnostic on the engine and came up with an oxygen-sensor error and a sporadic misfire on #2 and #6, but it misfired again this week. I've been told it's possibly an electrical problem, fuel injector, or a distributor cap or sensor.

Answer: The dealership confirmed a failed oxygen sensor, but you didn't replace it? Now the engine's running bad, the "check engine" light comes on, and you're asking why? Replace the sensor. A bad oxygen sensor can get to a point where it sends a false, high oxygen content signal to the computer. The computer, based on the incorrect data, will send large amounts of fuel through the injectors to richen the air/fuel mixture. This excess fuel can foul the spark plugs, cause a misfire, and make your engine run poorly. If the problem is still there following replacement of the failed oxygen sensor, then items like the ignition coils (no distributor on this one), fuel injectors, etc. need to be evaluated. Keep in mind that this engine has had issues with excessive carbon buildup on the exhaust valves, which may cause oddball multicylinder misfire conditions. This carbon buildup will require a compression test and partial cylinder-head disassembly and inspection to confirm the problem.


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