I have a friend who has a d16z6 in his 93 HB... His car hasnt been running for awhile so I went over to give him a hand. We ended up doing a compression check and it was kinda odd. As the car would turn over the car would hit about 80 PSI and drop PSI as fast as the car turned over. So it wouldnt even stay at 80 psi. We did all cylinders and all the same with psi slightly lower or higher. We did the test 4 times then tried it on my motor and the tester worked fine on mine? Any ideas... I thought valves or headgasket?