I ran a compression check on my 86 350. All cylinders were runing around 170 except 1, it was around 90. I left the tester on for over an hour and it only leaked a few pounds. What should I do next? Does this sound like a burnt valve? I checked the valves and #3 seemed to be tight, this is the cyl that is only running 90lbs. I adjusted to the proper setting but it didn't change anything. Any suggestions?