ok so my rev limiter is set for 8600 and my stock si clusters tach wont go past 6800, it was working fine when i got my car tuned for like a month then it started acting up.. ive replaced both the icm and coil and it still wont go past 6800 but the car does feel like it runs great and is going to 8600... any ideas of what else it could be? ive spent alotta time reading thru related problems in the search but everything says replace coil or icm and ive done that already.. any help would b great thanx

 

loose ground