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Old 10-21-2012, 08:37 PM   #1
Scooby Newbie
Member#: 247937
Join Date: May 2010
Chapter/Region: NESIC
04 wrx wagon

Default oil on plug on first change, missing after seafoam, 2004 rs

i changed my plugs after i got my new 04 rs this summer they were ngk racing changed them to Bosch double platinum and i gaped them correctly
... engine was running smooth idling fine just like i originally got it im not sure if it was running at 100% but there was oil on the original plug so i decided about a week ago to run some seafoam through the vacum line attached to the brake booster line and ever since then its had a very low idle maybe 500 or 600 rpm but the power is still roughly the same. but i was worried so i got it read by a friends obd sensor reader and it said either number 4 plug wire or coil and possibly the plug itself which i hope is the only problem...

anybody have advice on what i should do i dont feel like shelling out a ton of money for coils wires and plugs but id rather that then a lifter problem a blown head, or head gasket (not as bad but still a pain in the ass). i still may level the head by having it filed down smooth and level then change the head gasket... but that's latter on when it gets a bit warmer.

let me know your opinions and ideas, this is not my first subbie or problem with one and i love them and i rally race but i sure as hell don't want to do a engine swap.
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Old 10-21-2012, 08:53 PM   #2
Scooby Specialist
Member#: 217257
Join Date: Jul 2009
Location: Niagara Falls, Canada
2008 2.5i hatch
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your not supposed to use the brake booster line for seafoam on these motors. the line only feeds a single cylinder... I don't know what the remedy is now, or what issues it will now cause, but I'm sure that this is what started the "roughness"
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Old 10-21-2012, 10:14 PM   #3
NASIOC Supporter
Member#: 165749
Join Date: Dec 2007
Chapter/Region: South East
Location: Central Floriderp

There are a couple very simple steps to take to eliminate components from being the problem. Move the plug to another cylinder and see if the problem on the scanner follows the plug. If so, easy fix. If not, try the next part on the system. Keep going until you see the problem move to another cylinder. While you have the plug out, inspect out for abnormal signs and damage.

FWIW, It seems like half the time there are rough idle or misfire problems right after changing to a Bosch plug, it turns out the plugs just don't work well the ej engines.

Also, I don't think you are supposed to gap plugs with platinum or iridium electrodes, or check the gap with a metal gauge. Very easy to damage the surface.
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