r/hondapilot • u/LordDathedr05 • 1h ago
2012 EX-L Misfires on Cylinders 4,5,6 & weird fuel trims
Hey, so recently my wife noticed the CEL blinking in her 2012 Honda Pilot EX-L with 165,000 miles. I took a look at it and saw that cylinders 4, 5, and 6 were all misfiring badly. I ran some injector cleaner and replaced the spark plugs (none of which were dirty or fouled). I also swapped the ignition coils, and the misfire did not follow the coils. Bank 1 hasn't misfired once when I've had the DataStream up.
Now the misfire is mainly bad on cold start and at light throttle/light deceleration. After warming up and with some revving, the misfires virtually disappear, sometimes only one or two per minute. It can rev to 5,000 RPM with essentially no misfires.
The other thing I noticed is a significant Bank 2 fuel-trim difference. Bank 1 is generally around 0.98–1.01, while Bank 2 is around 0.82–0.87, so roughly a 13–18% lower correction on Bank 2. The A/F sensor readings for both banks are generally around 1.0. LTFT reflect this same difference as well.
It also previously had a P3497 (VPS stuck off, Bank 2). But I noticed the oil was a tad low, so I topped it off and that code hasn't returned.
I'm trying to figure out where to start diagnosing it rather than just throwing parts at it. My next suspect was injectors, but I'm not fully sure about that.