1997 Ford F-100 misfire po301 po304,po306.o2 senor to lean

1997 FORD F-100
13,674 MILES • 6 CYL • 2WD • AUTOMATIC
Avatar
HJ72
  • MEMBER
  • 23 POSTS
hi guys i got a head ace again!truck came in with light on hook up to sacnner codes where.
po301,po304,po306,o2 sensor to lean!things i did.
1-check o2s had 1 that was not responding read -3.0? unplug it did not change.replace it (good).
replace spark plugs they were foul bad replace coil pack and wires,fuel filter was never changed replace.claer codes run good!then light back on cly.4,cly 6 and down stearm o2 sensor change o2 clear codes light comes back on.i check for vacuam leaks fuel presure 30 lbs.any help you can give?i have 3 days in this one and even check for bad grounds!
Mar 26, 2010 at 9:40 AM
Advertisement
Avatar
RACEFAN966
  • CERTIFIED EXPERT
  • 5,029 POSTS
Ok so have you checked the injectors for cyl 4 and 6 to see if they are working? Ohm them out and get back to me with the ohms and I will look it up to see if they are in spec.
Mar 26, 2010 at 10:19 AM
Avatar
HJ72
  • MEMBER
  • 23 POSTS
i can only get to #4 the omhs are 13.39 and i took out spark plugs and they where firing.
Mar 26, 2010 at 11:39 AM
Advertisement
Avatar
HJ72
  • MEMBER
  • 23 POSTS
i just cleared all codes and light came back on po304,po306 misfire my fuel trim says -1.0-.05 i stll have 1 o2 sensor that is acting up it reads 25 with a ? it dose not switch?i check again for vacuam leaks.HELP!
Mar 26, 2010 at 1:21 PM
Avatar
RACEFAN966
  • CERTIFIED EXPERT
  • 5,029 POSTS
Ok so the O2 that is acting up is it one of the new ones? The injectors should be 11-18 ohms. The Codes points to the secondary air injections system and so with that I need to know if you have checked the coolant temp sensor? If not when the truck is cold unplug it and ohm it. Get back to me with the ohms and the temp at the time you check it.
Mar 29, 2010 at 9:14 AM