1998 F-150 4.6l 66k.
Occasionally when attempting a cold start the engine will fire but will not idle on it's own. This does not happen very often, but when it does the only way to keep it going is with the throttle. After a few minutes it will eventually idle.

Is this a problem with the IAC (idle air control) or computer or some other widget onknown to all those without a code reader?

I've had it checked, no codes are stored.

Problems like this make be long for the days of carburators, coils, distributers, a big shade tree and a few cold ones.

 

Hey there this is my first post, but I had the same problem. I replaced the vacuum ( I think) control valve. It gave me lots of heart ache and I plugged the control valve in and it worked just fine.

 

You can try cleaning it before replacing it, it is located on the side of the intake, and mounted with two small bolts. open it and clean it with carburator cleaner, find a cleaner that will not damage O2 sensors just to be safe.

 

What jr said......

 

Thanks for the information. I will try cleaning first.

Do you think this vacum problem could cause an occasional miss at highway speeds in overdrive and low RPM. A small increase in throttle will sometimes create a miss, More throttle will cause a downshift and everything is normal.


Thanks again