I have a 06 wrx for about a year n a half now, not long after i got it the cel came on and it was 3 misfiring cylinders, brought it to the shop they fixed it k cool. Then, like 6 months ago the same thing! got it fixed again. NOW, like 2 weeks ago i was driving, i hit the gas hard in 3rd gear and it backfired big time, 3 big bucks and 3 big pops at about 45-50 mph, immediatly the cel came on, SAME THING (misfiring cylinders). They replaced my spark plugs, coils, fuel pump, and fuel pump harness to fix it. The cel is off still and it feels ok, but occasionally if i hit the gas hard it does the same thing, hard bucks and pops out the exhaust, does anyone know why this is happening
Ps. My mods are... Catback, catless downpipe, cai, boost control solenoid, and got it tuned at Metric Subaru on Long Island.