2002 Suburban idle off, transmission?

I have an '02 Suburban with 202,000 miles. I have never had any major problems with my car. We take frequent trips to the mountains with it, have pulled many a trailer, etc and it has always ran great. Recently, I’ve noticed the idle seems to be sporatic, particularly when it’s really cold (20’s). I park in the garage but it is outside during the day while at work. There are times it seems like its going to die while sitting at a stoplight until it gets really warmed up. However, yesterday, when I started it (temps in the 30’s) it started fine but then all of a sudden, revved (sp?) up to a point I thought my car was going to jump forward on its own. I’ve checked Anti-freeze and get the oil changed and serviced regularly. I have noticed the oil guage bouncing around some, not bad and not all the time. There has been an occasion when I thought the transmission might be slipping or going out but then I won’t have any trouble. Any thoughts on what it could be? I’ve debated about getting another car but I LOVE my suburban.

When is the last time you had new spark plugs? Wires? Does the vehicle have a distributor? Air filter? Fuel filter? Any of those things being worn / old whatever can create problems in how it runs. Changing the oil and antifreeze won’t have a thing to do with rough / uneven idle.

If all of the basics are up to date your suspects, I think, would be first a dirty or failing idle air control valve. Or second a vacuum leak.