Rough Idle

[fivemustangs]

I have recently had my car tuned with a mustang dyno, When I got the car back the HP was a lot lower then it was rated for as described in another thred I posted. But the problem I am facing now is when I start the car it reves up to about 2000rpm and takes about 10-15 seconds to get down to 900 were it idels at. Then when I am crusing down the road and I put the clutch in it does the same thing but takes only about 5-7 seconds to get back down to idel. But the most annoying thing is sometimes when I put the clutch in the cars rpms drop down to 0 and stalls out and I can understand why! its not all the time but often enough to be a pain in the ass! So if someone could please point me in the right direction that would be great!
Thanks

 

[HISSIN50]

Look for a vac leak.

 

[Stanger007]

I would take it back if it has done that since the tune. The car should drive like stock or better after it is dynotuned!

Wes

 

[fivemustangs]

I thought maybe vac leak to but the idle gets back down to 900 were he set it, but its just a little slow. I should take it back and have him fix it, but I don't want him to mess anything else up, not sure if he really knew what he was doing. also still not sure about the stalling?

 

[2Many]

Check the IAC. I had weird issues with one, when let off it would stay high and slowly come down.
I was never able to get it to work right with the my PMS System.
Not sure if it was the tune or bad IAC, sticking.
It is unplugged now. With it unplugged it won't idle til warmed up a lil, but after that it idles fine and throttle revs up and down perfect.
I don't street drive this car anymore so I didn't care about cold start.
I would think you could warm up the car and then unplug the IAC and see if the hanging rpm problem goes away.

Just a suggestion.
Good Luck.

 

[corey97svt]

On my 94 I had to unplug my iac completely and create a vac. leak to get my car to idle it had similar symptoms.