My '99 4.0 OHV only has 88,000 miles. It runs excelent 9 months out of the year. When the weather gets cold, it takes longer for it to start. It came with a block heater when I bought it. When I am at home, I always have it plugged in. However, when I am at work, there is no place to plug it in. If it is left unplugged overnight on a 10 degree night, there's a good chance it won't start in the morning.
I have never had a vehicle that I have had to plug in before. It just seems that there has to be something wrong. My old '92 4.0 had 198,000 miles and it started on days where it was 10 below.

 

Sounds like the symptoms for a bad Idle Air Control (IAC) servo. When it's warmed up and idling, try turning the steering all the way to a lock and hold it there for a second or two. Does the idle speed drop at steering lock? If so, that's a pretty good sign that the IAC is not able to compensate for increased load at idle or a cold engine.

Another item to check is the condition of the spark plugs, spark plug wires, and filters (including fuel filter). When's the last time a tune up was performed? I'm assuming the engine idles pretty well once it's running and up to temperature.

-Rod

 

Computer uses the engine TEMPERATURE also to determine whether richer mixture is needed. If Engine Coolant Temperature Sensor (ECT) is bad, and telling PCM that engine is HOT when it is NOT, hard starting when cold can occur.

 

got a question...would the cold weather make it hard to start or could it keep the battery from holding charge also?i am in kentucky and it is snow.cold.ice etc...now i can not keep my battetry charged. i am going to take the alternator off and have it checked in about a hour but would the weather hender my battery?sorry to butt in on you guys by the way..