Quote Originally Posted by 02blackz View Post
im goin thru the same prob!!??, i went to autozone to have it scanned and P0300 popped up. i already changed my plugs-ngk tr55, and wires-msd sc8.5, but still no change. i need to try to do the pressure test or open up my v-covers to see whats going on in there cuz its hurtin pretty bad.

BTW-i went to a cousin of mine (a chev. hater) and said it was becuz i put the perf. wires and plugs. i honestly dont think so bit he did make me doubt what im thinking (internal problem). he made me switch ign. coil #1 w/ #3 and the problem persisted. but ignorantly that was his explanation and wanted me to buy stock acdelco wires n plat plugs. this forum is helping me more than you guys think so any more comments comming here could help someone else, thx!!!
Don't listen to your cousin.

As long as you're using good quality high performance plugs and wires (I see you're using NGK and MSD, which are good) the problem most likely isn't with those components.

Definitely open the valve covers and check everything out. Pull the pushrods and roll them accross a glass surface (table is good) to see if they are bent. Inspect all the rocker arms for cracks or damage to the roller fulcrums. Check to make sure none of your valve springs are broken, either.