1988 Ranger problems part 2?

Question

well i am back .. and i changed the MAP sensor and i checked out the ignition module... did a fuel filter change and a Fuel Pressure Regulator change .... its the famous 2.9 V6 and for those of you who know there is no EGR on this motor . .. i am still having problems with the truck dogging down while driving almost as if ... the fuel filter was clogging or something but yet ... the truck will idle all day long and no problem and rarely stalls .... and the check engine light doesnt come on ... and i bought one of these . Actron code scanners for Ford and the only thing i get is ... the Oxygen Sensor is running lean and does not switch .. and i have done replaced the Oxygen sensor in a vehicle before with .... with the same problem it was running rich or lean and changed it and it told me the same afterward .. so i cant think it is that sensor either ...... ... doesnt seem to be any Vacuum leakes .. and when it dogs out seems to put out a bit of smoke black smoke ... any ideas anyone?

Answer 1

Check the forums here if nothing else comes up---http://www.therangerstation.com/
Black smoke would indicate running too rich--could be semi- plugged cat converter? If O2 is new and still get a code, maybe the wiring or connector is corroded---will give a false signal to the computer. You'd need a service manual with specs for O2 output signal to check. Could be a fuel leak in the carb/injector...maybe run some FI cleaner through the system a few times.

Answer 2

You have not replaced the O2 sensor in this vehicle. That would be the next thing to do. A faulty sensor could indeed cause rich and lean conditions. If the new sensor still says lean, then try spraying around the intake manifold with a flammable spray, to see if the engine idles up.The only other thing would be the injectors, as those were not the deposit resistant type.