94 3.8, knocking on startup

My car runs great, but after it sets for several hours, it knocks upon restarting. It only does it for a second or two, but im worried that this could be a sign of a worse problem.

That type knock is likely from the late rise in oil pressure. The oil filter you have has the no drain back seal, I know of none that doesn't but you could possibly have one or it is broken.

thanks for the info

Sometimes if the bearing clearance on the crankshfaft is increased, you can get a knock upon startup until the oil pressure compensates to fill the gap. If this is the problem, I don't know what could be done about it short of an engine overhaul with new bearing placement. Can you hear the knock if you rev the engine and then let off the gas?

Nope, only at startup. No other strange noises at undesirable times.