Need help on code it's po125 closd loop fuel ctrl an insufficient coolent temp. What do i need to look for or what parts do i need.The engine is 5.4 Thanks

 

first thing to do is check the thermostat. it may be stuck open causing the temp to stay colder than needed when the vehicle switches to closed loop fuel operation. the other things to check would be the engine coolant temp sensor or even low coolant level. P0125 indicates that the required temp hasn't been reached within a specified amount of time after engine start up. if you haven't changed the thermostat that is probably your problem.... let me know how you make out.

 

I will check them this weekend .I know it's not low on coolent that i have checked. When the service lite come on after it been driven a few hundred miles on long trip's.In cool wether Think You for the info hornet347

 

I have an '01 Screw 4.6l that had the same problem. Last summer the check engine light was intermittant. When it got cold out it was on all the time. I remember my mechanic saying it was a minor issue.

Anyway, did the right thing, checked the code at AutoZone, checked here, & got the new t-stat. My truck warms up within a mile of slow driving & runs better too. Cost me about $15 and 1/2 an hour. Only had to remove the carb shroud - 3 bolts. Drain the radiator to below the level of the upper hose @ the passenger side petcock behind the lower part of the passenger wheel splashguard. Pliers to slide the hose clip back, remove the hose, remove 2 housing bolts & there she is. Drop in the new t-stat & o-ring bolt back up, top off with fresh anti-freeze & you're good to go.

I didn't do anything to reset my ECU, the light went off after driving a few times.

Only thing I noticed is that now my outside air temp thermometer is showing a much warmer temp than it should. It was 37 this morning and it reads 73 after the truck warmed up. Any ideas?