ok so i have 02 civic si...i just hit 93k on the odometer..all the regular mantaince on this car has been regularly done since ive owned the car (bought it w/60k)..just recently the car began to drive very sluggish and very slow (atleast to how it was running before). Automatically i figured it was the spark plugs..so i replaced them with the ngk iridiums...the car runs a tad bit better now but it still does not run clean and smoothly up to redline...at times under normal driving conditions it gives almost like a small hickup or a gentle quick bog while normally acclerating in 1st or 2nd gear..it just doesnt feel right...feels like the motor is working way too hard..and the car feels very sluggish..ive recently flushed the transmission..replaced the clutch..changed spark plugs and oil...so my question is..y is my car all of a sudden acting like this?...could it be a failing coil pack? if so how do i check..r my injectors failing or do they need to b cleaned?..or maybe is my car just due for a tune up? I dont really feel like taking the car to the stealership so they can charge me crazy money for simple stuff..could it be that my car needs a valve adjustment? ...has anybody had these kind of problems before..and for the people who have done the 100k tune up, what exactly did u do during the tune up?...(btw i dont have a service manual) i dunno...any help,inputs or suggestions will b greatly appreciated...thanks in advance guys