ok, funny thing is that im experiencing this in my 420a eclipse, at first i was scared out my ass that is was a rod know or spun bearing, but i have driven the car within time and time and it still hasnt blown or spunn, and i actually floored it acouple of time in second gear and first gear and it doesnt wana blow or anything lol, but it does sputter.

it sound like a knocking/tapping sound. now this is where it get intresting, i have brand new lifters in the car beause previous ones where starting to click. so i put in these new ones, but i didnt know and after i installed them, they told me i had to take them to a shop and bleed them, so they told me to leave it alone and they will bleen them selves, noise will enventually go away, but seems like it just gets louder and louder, (its quite embarrising to drive, people just laugh) so yea, i dont beat on it, just like i floored it twice like i mentiones, but i feel like its performance has worn out, like it bogs and sputters time and time and spark plugs are new and wires and coil are in good shape. for some reason im thinking its valve adjusment, but idk how to do that. any tips on checking and fixing valve adjustment?