Hey Scotty. I have a 2010 Subaru Forester showing codes P0301 and P0303 for cylinder 1 and cylinder 3 misfire. Since both cylinders on the passenger side are misfiring, I'm concerned that it is not something wrong with an individual spark plug or coil, but something more systemic such as a timing issue. Thanks!
My moms 2011 Forester had the same issue. The coil pack cables were switched. It probably won’t be that simple but worth a check.
It’s worth a shot, I’ll check it out. Thanks!
If that car still has its original head gaskets they are probably failing. Subarus of that vintage are infamous for that problem, very few escape it.
Yes, original head gasket. I’ve been lucky so far with no issues. I’ll start with spark plugs and fuel filter and if those don’t fix it, head gasket may need to be next. Thanks for the input.
Usually the gaskets on those will start to leak externally before they leak internally. You could also use one of those kits Scotty has demonstrated to check for combustion gases in the coolant.
https://www.youtube.com/watch?v=v0U8Iyf0kk4
A 12 year old Subaru. It's either fuel or spark. When was the fuel filter changed, spark plugs? How many miles on it? When was the timing chain replaced? Have you had a compression test?
Thanks for the input. The items you mentioned have not been changed since I’ve owned the vehicle, so I will start there 👍🏻 ~90K miles on it
Changing out the ignition coil pack did the trick. I accidentally damaged one of the cables so that was replaced as well. No issues since. Thanks for the advice!
more systemic such as a timing issue
I think a timing issue would affect all the cylinders, not just two.
I'm pretty sure boxer engines have two banks, each with their own head gasket.
