Had the same problem with both my DS708 and Snap On Brick, no confirmation that it relearned crankshaft angle with a 200K mile 99 Chevy Astro with P0300(showed high misfire counts on cylinders 4 and 5. Relative compression and fuel injector flow tests confirmed no compression or fuel flow deficits. Checked wires, replaced 4 and 5 spark plugs and put on a new cap and rotor, helped a little but still saw misfire counts on 4 and 5 . Ultimately replaced the distributor assembly and resolvedproblem. After a new distributor Did the relearn procedure twice with no confirmation the relearn ever took successfully or not , but just let it go, because the random misfire issue was resolved.Maybe the timing chain seen better days, but as long as there wasn't a code , I'm not going to keep trying and end up blowing a motor.