#8 cylinder misfire
please help!!! I have a 1998 z71 with 350 vortec. while driving down the rd at any speed over 30, if i lightly let off the gas i get a buck, (sometimes worse then others). i thought it could be my torque converter, but the tranny went out so i had it rebuilt with new tc and new flex plate. problum still exists, i am getting a #8 cylinder misfire and a nock sensor code. i have replaced plugs, wire's, cap, rotor, distributer gear, 140psi compression. don't know where to go from here, don't want to throw money at it and hope to fix it. any ideas much appreciated.