My Crown Vic has a bit of a start up rattle. Not nearly as bad as the first start after an oil change, but very noticeable. When I first got the car, it had a Valvoline filter. After the first change, I went with the 820 and the sound went away. Then it started with the 820 once I passed 8k on my OCI. I change my oil every 10k and each time the noise comes back earlier and earlier. Now it started at 2k. Could it be a filter? I haven't tried an Fram Ultra since I had a stash of 820s.