Hello Mazda Forum,
I am looking at a Mazda 6 2005 - 6 Cyl with ~ 100k mi. The current owner says that these codes are up and wants to dump the car cheap:
P0300 - Random Misfires.
P2189 - System too lean @ idle Banks 2. A bunch of other System too lean incl Bank 1. (P2179. P2177)
P2197 - O2 Sensor Stuck Lean - Bank 2.
A week before these problems started, an oil change and transmission fluid change were done.
So what I want to know, is how to differentiate between a vacuum leak, O2 sensor problem, or timing chain issues causing the random misfires? I haven't ruled out a MAF problem.
I know to look at my scanner data and look for the O2 sensor controlling or being active, in which case, it is working. I know to look at trims if the sensor is working to identify vacuum leaks but the P300 code bugs me. It is exactly what you get if the timing chain tensioner is malfunctioning and the timing chain has jumped a tooth or two. So how do I diagnose that? How do I rule that in or out.
This will be done as part of a pre-sale inspection. Any ideas?
I am looking at a Mazda 6 2005 - 6 Cyl with ~ 100k mi. The current owner says that these codes are up and wants to dump the car cheap:
P0300 - Random Misfires.
P2189 - System too lean @ idle Banks 2. A bunch of other System too lean incl Bank 1. (P2179. P2177)
P2197 - O2 Sensor Stuck Lean - Bank 2.
A week before these problems started, an oil change and transmission fluid change were done.
So what I want to know, is how to differentiate between a vacuum leak, O2 sensor problem, or timing chain issues causing the random misfires? I haven't ruled out a MAF problem.
I know to look at my scanner data and look for the O2 sensor controlling or being active, in which case, it is working. I know to look at trims if the sensor is working to identify vacuum leaks but the P300 code bugs me. It is exactly what you get if the timing chain tensioner is malfunctioning and the timing chain has jumped a tooth or two. So how do I diagnose that? How do I rule that in or out.
This will be done as part of a pre-sale inspection. Any ideas?
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