98 explorer missing have p codes

[quote:cad68bdc14="mxrider39"]I have a 98 explorer sport with a V6, with 88,000 miles on it. I have replaced plugs and plug wirers. The codes on the ODB II reader is p0303 and P1151. I have check the plug and wirer on #3 cilendar and I have spark. Am I looking at a bad injector???? What about the other code says o2 sensor witch one?????[/quote:cad68bdc14]

I need to know whether its a dual or single exhaust for P1151 relating to heater O2 circuit cutting out on B2S1. A single has 2 sensors and a dual has 4

Also about PO303-when you changed the plug and wires does it continue to show? Could be a vac leak/burn exhaust valve/injector etc.

It is dual coming off motor then goes into single, then to kitty, then to muffler. I switched plug, and wire and it still comes up as misfire on cylinder 3. The p1151 code is telling me lack of HO2S21 switches sensor indicates lean.

Were do I go from here?????

Thanks

just wondering if any body could help me???

Pull the plug on cyl 3. Is it white? I have seen both injectors and coils go bad in those. Check for hot spark (blue) If got good spark, then Id go injector