Foxbodyforever

So, like everyone else my car's idle is surging. It only happens after the car is warm and when it is in reverse or drive. If i put it in neutral it settles but when it's in park or neutral the idle is always high. When i start the car the rpm's go up to about 1400 and then slowly drop to around 1000, which is still a little high. I'm pretty sure all this means a vaccuum leak so which hoses should i check?

1991LX5.0

easiest way to check is to spray a little starter fluid around and see if the idle rises, if it does you know you have a vac leak

67mustang302

Brake cleaner works too.

RRyder01

Just hunt around for it...maybe you'll get lucky like me and hear it hissing. Mine was the one underneath the top intake and I didn't notice it until I stuck my finger down there and it nearly got sucked in! Anyway, good luck!

1990NOS!

when i blew my lower and upper intake my idle didn't surge like that.....
But to just check do like 1991LX5.0 said to do.... spray carb cleaner around your u/l'r intake gasket areas while at idle and be sure everything is tight (hoses, bolts/nuts, clamps..etc..). Sounds like you make have a loose hose somewhere though. keep checking GL

VASSAGO

check ur iac bro