Does the 4.3 v6 have a cam sensor

Yes, there is both a crankshaft position sensor and a camshaft position sensor. But I would not focus on those for your concern. Check for air intake issues, crankcase ventilation issues, engine timing issues, exhaust issues, emission system issues. Hands on inspection is needed. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops