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Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.The compression reading you are getting on this cylinder indicate you likely have a valve seating problem either due to a bad valve guide and or seat. The 90 PSI is to low even for the first crank. I would do a running compression test on two known good cylinders as well as the #8 cylinder and compare the readings with the #8 cylinder. The reading on all of the cylinder should be pretty close to the same. If the #8 show lower then the known good cylinder then your problem is with the valves and or valve guides on that cylinder.