Ok i have a D15B7 and it makes a knocking noise. It knocks a few times when its idling after you rev it. And second when i it is sluggish until about 4000 rpms then you feel a lil boost of power. What could be wrong.

well if it knocks could be rod knock

pop the hood and lisun if its in the bottom it mite be a bad baring if its in the head it could be a bad valve a bad spring or a bad rocker arm as far as the power loss it may have jumped time

for now get a compression tester and check all your pistons
for your motor it shoud be
90 low
100 ok
120-up good

i had a 89 teg like that so i pulled the head off and i had 2 cracked valves

thanks alot i'll check into it, if i can ii might try to upgrade to a Z6 if i can find one.

Change the rod bolts and rod bearings and get the valves adjusted