2000 Chevy Venture can't find hesitation/studder, suspect en

3.4L-Had a code for camshaft positioning sensor. Did voltmeter test and determined it was bad. Replaced sensor and everything was fine. Short time later developed a studdering or missing sensation while driving. Soon after Engine lite. Downloaded codesP-0131- o2 circuit low volt sensor 1
p-0137-o2circuit low volt sensor 2
Sensors checked out ok cleared codes. Still have this studdering miss mostly while driving, sometimes while at stop in drive. Sort of felt like trans, but no shavings in pan, fluid fine even flushed transmision. Not getting any more codes. Also changed fuel filter. Engine seems to idle fine and respond well. I could use any help at all. Tommorrow I'll check fuel pressure and intake suction. Please give me a clue!