For a while my coupe was playing up (missfire, Boost problems). First i changed the bcs and it made a big improvement on the boost side well apart from the missfire. Then today i was looking at all the options that most other people on here has done and found one solution that has worked like a treat and that was to gap the spark plugs to 0.67 on my denso ik20. Now i would of gone and brought a few items like coil pack,afm,new set of ik20s,o2 sensor. The reason i didnt is because i didnt get no eml on or any codes stored so tried the gap solution and WOW what a diffrence it has made, feels like i have had my car mapped again.
Any one that is getting the same problem i wld try this first.