I have a 01 ranger 4.0 ive owned for just over a year now 288k miles, i really cant figure this out or find anyone else with the same issue, in the winter/cold around 50-60mph it has a random bucking/ feels like fuel/ignition cut the rpms drop for a split second then it goes back to normal. it does it maybe once every 2-5 minutes when its cold/snowing out which is like half the year in michigan. it wont do it all summer or when its raining, it also has a low idle when the engine is warm around 600rpm but runs fine no lights are on, it doesnt throw a code. what should i look for? im not totally sure were to start, i checked all the plug wires and coil pack and wiring everything looks fine. im not sure what could cause this

 

well first off , have you replaced both the ignition coil and ignition wires with

 

I have a 93 4.0 2wd that was having similar problems. The best advice I can give you is to pull apart all electrical connections and put some di-electric grease in them. It sounds to me like the cold could be causing the metal to contract and it's not making good contact. I know that sounds to simple, but it really could be that simple. Mine started doing the same thing and I ended up replacing everything electrical including fuel pump only to find that it still wouldn't run right. Then I read about the connections thing and tried it. It has ran right ever since. Just saying.
As far as the idle, I would suggest a tune-up with new plugs and wires. And maybe clean or at least check the IAC (idle air controller). Or maybe just adjust the idle.
Good luck.

 

some 2001 - 2003 ranger / mustangs / explorers with the 4.0 litre v6 engine

the factory ignition coil casing would fail allowing pent-up voltage to escape

i had to replace my coil because of the same issue , but my truck is 2010

 

thanks guys ill mess around with it a bit more today and see if i can fix it

 

What all connections are you referring to with the di-electric grease?