03 400 and it has little or no compression, I first disconnected the manual decomp cable and adjusted the valves...still no compression. I pulled the cover and nothing out of the ordinary, kicked it with the cover off and no compression. I then pulled the cam and checked auto decomp "plunger and spring which looked good. I kicked it over with the plunger out and still no compression. so, I hooked up a leak down tester and at tdc I had only 10% leakage, but was unable to register anything with the compression tester, so that has me a little boggled...still thinking it's the auto decomp??? Q: Dose the auto decomp plunger seal the port to the cylinder? Q: Which direction should the auto decomp assembly on the cam rotate freely. any advice would be appreciated!!