My z is making a knocking noise coming from around the oil cap area. It doesnt do it all the time just when it feels like it i guess. I tried puting my hands on some parts to see if it would stop but nothing. Im gonna take some video footage tommarow and maybe someone knows the answer.

 

I think youre due to an OIl change and or you put to lightweight oil. try uh Mobil 1 synthetic 10-W40 motor oil.

 

2nd the oil change idea. And watch your oil pressure level closely, trust me. If it still does it after an oil change, do a couple full throttle passes because it could just be an air bubble in a lifter and high rpms and a lot of load on the engine can fix that. If it still makes the sound after an oil change and you beating on it, you might have bad lifters (or, if your oil pressure is low, you might be starving the head of oil and need a new oil pump; I don't know anything about the maintainence of your car, I'm just giving possibilities).

 

Z lover thanks alot i just called the guy i bought it from he said its need a oil chage. I tole him about the knocking noise he said it might be the vavle springs. Im getting the oil change next week see if that helps. He never used synthetic oil and im gonna swtich over. He said to use 20w50. I think i might just use 10w40. When i give it some gas it seems to go away. Man these cars are so complex, but dam there fun to drive.