KV57 Posted March 26, 2016 Share Posted March 26, 2016 HiI own a 2007 Forester XT, I love it but I can be a bit OCD where my car is concerned, I am a aircraft engineer by trade and really am a bit difficult about things being right.The car has a full subaru service history with every stamp.On medium throttle it feels like there are flat spots in the middle rev ranges, seeing as the engine has done 100k I just changed the o2 sensor and maf sensor anyway as they were not expensive and at that amount of miles I would want to have done that before I start chasing power anyway, the flat spots are still there, I pulled the plugs and whilst in perfect condition and look quite new they are Bosch FR7N133 which is the bosch plug for these engines, I note that ngk should be used and honestly I have had issues with bosch plugs on a audi before, is the Subaru picky with plugs and would I be better off fitting the ngk's?Thanks for your help in advance Quote Link to comment Share on other sites More sharing options...
Jay762 Posted March 27, 2016 Share Posted March 27, 2016 Plug gap is important but as you have a flat spot not lumpy running I would have thought it was more a air / fuelling issue. Has the flat spot appeared recently? Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted March 27, 2016 Share Posted March 27, 2016 Most of us run ngk 7's with a slightly smaller 0.65 mm gap in higher boost aplications (remapped ) As Jay said the air and fuelling could also cause flat spots . When was the last time the air filter was changed and do you use the same octane fuel everytime ? If it's not broke .....upgrade it 😊 Quote Link to comment Share on other sites More sharing options...
KV57 Posted March 27, 2016 Author Share Posted March 27, 2016 3 hours ago, savage bulldogs said: Most of us run ngk 7's with a slightly smaller 0.65 mm gap in higher boost aplications (remapped ) As Jay said the air and fuelling could also cause flat spots . When was the last time the air filter was changed and do you use the same octane fuel everytime ? If it's not broke .....upgrade it 😊 yeah it had a full service at 100k, all fluids and filters , new air filter, might just swap a walboro in with an external wrx filter in the bay Quote Link to comment Share on other sites More sharing options...
KV57 Posted March 28, 2016 Author Share Posted March 28, 2016 new ngk's in and flat spot gone...yay 2 Quote Link to comment Share on other sites More sharing options...
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