My friend has a GMC pick up and had just got a bad idle when the engine is cold. He has to keep his foot on the gas to keep it from stalling. Once it warms up it idles fine. It has been very cold lately here. In the teens. He says once it warms up it seems to be ok.
He just told me this morning it stopped doing it. I have not looked at it but I suspect something to do with the throttle body or a vaccuum leak. Would a fuel pump going bad do this?
Give us the year and engine size,fuel injection type if it is in a “crossover year”. You could also let us know about maintiance,any check engine light?
I can remember the day when “maybe it has a vacuum leak” was a very real possibility, I got a "too lean"code on my 2004 F-150 and looked around for possible vacuum leak points, there just aren’t too many places for a vacuum leak to happen these days, just not like it used to be.
You should get a Haynes manual and go through the checklist for that problem or get familiar with the related parts.