It appears you already have a good set of coils, start with plugs, buy good ngk plugs. These engines eat plugs especially once you start throwing boost at them, I’m running one heat range colder than factory in mine right now after smoking a factory spec set but I’m pushing 20psi so your results may vary.
Owner reviews for spark plug
Ive been using the Brisk USA Premium Racing Spark Plug 14mm... yeah I get it they are kinda expensive when it comes to spark plugs at little over 13 dollars a piece but trust me they are worth it, ive never had good luck with any of the spark plugs listed for the 2.5l, specially not with what I've done to it, iridium plugs, platinum, copper, Nicole, even ruthenium plugs.... but these Brisk plugs are killers, ive never had my car run this well before, even my throttle response is better and the heat range is correct as well..
When I had my Ford Raptor tuned I went with these as recommended by the tuner and they have been superb
Running the ruthenium plugs. Works good for me FR6AHX-S (94279)
Definitely get NGK’s - the parts store I went with initially gave me other plugs and even with a new DIC the engine was still misfiring without NGK’s
Get the oem denso ones. There is nothing better than oem for that kind of thing.
NGK is prob the best sparkplug for performance, Denzo is a cheaper option but there not as good for performance
Today I replaced the spark plugs with new ones PFR7S8EG VW genuine. With new plugs car runs better, but idle still wasn't good enough.
To me it seems as a rip off, even changing sparkplug on Mercedes a class w169, which is a pain in the ass, won't cost as much.
Damn $40/plug, I have a nissan altima 2012 and got the most expensive one at $30CAD/plug NGK iridium laser and it was out of necessity as cheaper ones was out of stock during lockdown.
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