2007 Forester 4-cyl manual NA
CEL and flashing cruise came on, figured it was because it was overdue
for an oil change. Off and on, but most of the time on. Went off when
changed the oil but came back a day or two later. Suddenly begins to run
very rough and CEL begins to flash on way home.
p0420 (cat efficiency low)
P0301 (cyl 1 misfire)
P0302 (cyl 2 misfire)
and the MIL readings:
quite a list. where to start? are some of these codes being thrown on
account of the more serious codes (ie misfire causing o2 sensor reading
to be funky, etc)
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rough running, cyl 1&2 misfire
Posted 10 February 2013 - 02:13 PM
2007 Forester 4-cyl manual NA
Posted 10 February 2013 - 03:47 PM
P0420 is probably on because of the misfires. Probably just needs new spark plugs. How many miles on the engine, and when were the plugs changed last, if they've ever been changed?
Posted 10 February 2013 - 04:34 PM
the engine has about 128k bought it in august with 115k not sure if/when last time plugs were changed but will start there.
Posted 10 February 2013 - 07:17 PM
Posted 11 February 2013 - 10:04 PM
put new spark plugs in today. the old ones didn't look that bad although the passenger side rear plug (sry, i'm new to subarus, don't know which cylinder that is) had a little bit of oil on it. the gap didn't look noticeably out of spec. once installed i started the car again and it still runs like garbage.
Posted 11 February 2013 - 11:44 PM
The valve cover grommet is leaking and will need to be replaced fairly soon or it will short that spark plug and cause misfires. That could possibly be a cause of the current misfiring.
Does that engine have spark plug wires or individual coils mounted directly on the plugs?
Posted 12 February 2013 - 04:28 PM
it has spark plug wires. i found a video that advised turning the wires almost 180 degrees before removing in order to keep the metal contact in tact so i did that. how are you sure that the valve cover grommet is leaking?
Posted 12 February 2013 - 05:41 PM
Have never heard of twisting plug wires. Kinda sounds like bird to me.
Swap the plug wires front to rear and see if the misfire codes follow them. Or if they look old just replace them.
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