I think my cadillac has a rod knock in cylinder #2, when i was adjusting my timing, i heard the knock. I started taking off spark plug wires one by one, when #2 was taken off, the knock went quieter. But when i took the stethiscope to the rocker arm bolt on the other side, i heard the knock VERY clearly. The oil wasn't changed very often in my cadillac thanks to and old granny, and it only has 94,000 miles!!!! I am positive that the knock is my lifters because they may be dirty. The knock is not around AT ALL when cold. Other than that, the engine runs like a clock, nice and smooth. It may also be my #1 main, right? The main bearing thump was also present in HT4100's. It sounds like a mallot knock, my oil PSI is perfect. I changed the oil 6 times within the past year and the car has not been driven much at all, maybe twice on the road. I did another one just uesterday, but added tranny fluid before change, lifter tick is gone. I added lucas oil stabalizer, and my oil PSI went up. The knock has been present ever since i had the car. Under the oil cap, the rocker arms look pretty clean, a GOLDEN BROWN. My question is, which one of these is the knock? I have a flowmaster 40 series delta flow and the knock is simeltanious to the sound of the muffler, so it must be the lifter(s). Would the oil P.S.I drop with a rod knock?