2006 3.0 ranger code: p0306. Misfires randomly between random cylinders. We have replaced and done; Seafoam, spark plugs, spark plug wires, Coil packs, main computer, and fuel injectors. So the engine light will come on randomly and then disappear after 200 miles. But, 200 miles later it comes back on. Isles rough. Then goes away. What else should we do? Heads maybe? Let me know! Thanks.

 

Welcome to the forum

Yes, 2004-2006 Ranger 3.0l is most likely recessed exhaust valve seat issue, TSB here: https://www.therangerstation.com/for..._05-26-3.shtml

Heads can be rebuilt with new seats and exhaust valves

The TSB is for Ford Shops and they don't/can't do that type of work so they just replaced the heads

 

Have you checked your PCV valve hose? Mine had similar symptoms and I just happened to look up at the PCV valve and noticed that hose had pinched, therefore air blockage. Could be that simple for you as well.