I don't have much money to spend on parts I don't need so I was wondering if anyone has some insight to help me pinpoint this problem. 5.3 Has 244xxx miles with a somewhat mild misfire for while now, hard starting(cranks strong just takes a few seconds cranking to get going), it's generally fairly smooth, minus occasional vibration fits and a bit of hesitation. newer plugs and wires and I've got a mediocre scan tool I've been doing a few live data captures and rpms are only reading in the 500's while the tach shows 900ish idling. The only thing that's really jumped out at me is jumpy spark advance just idling and seems like one bank is having trouble with being too rich or too lean, right now my best guess is a bad crankshaft position sensor that is throwing off timing? I'm really not familiar with this engine and I would really appreciate any ideas from anyone who's had similar problems before I get the multimeter out and work in the cold.