My 3.8 is acting funny. I think its a vacuum leak, but y'all give me your ideas.

Last wedesday morning (early morning) it got really cold outside (freezeing temp). I went out at about 12:30 to start the car, it was parked outside in the shade, so it was still froze over, even though it wasn't as cold out by then. I turned the key, and it tried to start but it didn't quite make it. I tried again, and it started up, but it was idling high like 1500 but that goes along with the cold weather, but the car had a little shakey stumble feel, so i figured i'd just tap the gas and give it a little to let it level out, and it stated shaking worse when i gave it gas, but when i let off and it went back to idling at 1500 it only had the same little shake, so i let it sit for a few minutes, then tapped it, and it was fine. Since then it'll do the same thing if it has sat all night in the cold when you start it.

What tipped me on the vacuum leak, was yesterday i was out christmas shopping and i had the heat on blowing from the floor. But i got warm and turned it off. Now i know GM has astro-ventilation but whenever the car would downshift and pull more rpm's it was start blowing like i had the fan on ouf the floor and defroster, even though it was turned off.

Now does anyone have any ideas?

I figured when it froze on wednesday morning, it probably cracked one of the hoses and now it has a leak, but thats just my idea. I haven't really inspected under the hood too much. Once its warmed up the car doesn't act sluggish or anything, it just has a little shake at idle. So i don't think its misfiring, and the SES light has not come on.

 

no one has any ideas?

 

could be a bad IAC

 

my car is fine and that has always happened. it happens especially when going up a steep hill at speed. even if the fan is off, the air starts blowing to the feet and defroster.

what sounds more to me from what you describe is your car running really rich. I think its called "chocking". anyway, check the IAT sensor. another thing I could think of is your ignition. depending on how many miles are on the car, you might want to replace your plugs and wires. the plugs hold up really well, but t he wires go quite fast. but if you're going to swap out the wires, might as well get the plugs..

 

the plugs and wires were replaced around 98,000 and it only has 116,000 on it now.

 

if youre running rich your plugs will be shot, its only 10$ for new ones. do them

 

Idon't think its running rich. It doesn't smell like it is.