Mrod1012

So last week I was driving my car and decided it was a little to hot out so I turned on the A/C. The air started coming out from the defrost and floor vents but not the dash so I automatically assumed vacuum leak. Once I got home I saw that the line running from my bypass valve to the the vacuum line that runs into the fuel rails was cut. It looked as If someone went in and split the two but I know for a fact no one did because the car stays in the garage while I'm at work and isn't a daily driver. So I went to my local auto parts store and got some connectors and boom problem solved the A/C ran fine. But then the next day I noticed my idle would jump from 500-800 and then drop to about 400 and then do it all over again, so I got under the hood and thought "damn another leak!" but I couldn't find one so I thought the connector I bought may have been defected so as I disconnect the the vacuum lines to check the connector the idling goes back to normal....the car sits at about 600 and doesn't jump, but when I connect the lines back up the idle starts to jump again! Shouldn't it be the other way around? Oh and the car is a 2002 GT with a V-2 Vortech. Anyone know what it could be?

1998Slow 'Stang

Try unhooking the battery for a few minutes and then fire back up with the vacuum leak fixed. It could be possible that the car compensated for the vacuum leak without you noticing.

Mrod1012

ok sweet I'll try that and let you know what happens. Thanks for the tip.

Mrod1012

Well I disconnected the battery waited 3 mins and hooked it back up, started the car and the idle still jumps. Maybe I need to drive the car around a little bit so the computer has some time to re-learn?

Mrod1012

Anyone?????

Tom V

Mrod, I want to clarify I an no a mechanic. I only do small things with my car. Cleaning K&N etc.
I seen this the other day in my Haynes so I dug it back out. It says "Caution: Do not disconnect battery from the vehicle to clear codes. This will erase stored operating parameters from the memory and cause engine to run rough for a period of time while the computer relearns the information".
Hope that helps. I would appreciate it if someone better at this than I would come by and clarify.

Mrod1012

Thanks Tom V. I'm hoping someone can help me figure out what's wrong.

1998Slow 'Stang

See as that didn't help I would first check for more leaks, second with the car hot and idling unplug the IAC and notice any change in idle. If the it drops or even stalls your IAC is good. If it stays idling the same your IAC is suspect....

There are some that say an IAC from your favorite local auto parts store is fine but I have never had much luck with them lasting more than a couple months.

Mrod1012

Well checked for more leaks and couldn't find any. Disconnected the IAC and the car stalled. So that's good. It's just weird because when I hook the vacuum line running from the by pass valve to the line running to the fuel rails the cars sounds like it wants to stall but when I create the leak the car runs fine.

Mrod1012

Lol I feel like a moron. So after spending hours and hours reading forums and talking to people at Vortech come to find out there isn't anything wrong with the car lol. The only I need to do is cap off the vacuum line running to the fuel rails. The vacuum line running from the bypass valve doesn't connect to anything because the bypass valve is set-up to vent into the ATM. I had the car worked on at a speed shop which I kinda had a bad experience with and when I first picked the car up everything ran fine. It wasn't till the A/C started actin up that I really got under the hood and looked at everything. I thought maybe the lines bursted under pressure but come to find out the cap on the vacuum line going to the rails fell off. I'm gonna cap the line and run the A/C if it runs fine problem solved.