Engine Idle Issue Just Started Today

[cdurbin]

Hey Guys,
I'm not sure what happened but my 91 started running strange this afternoon. Today we have had record heat index here in Charleston. Long story short, I had to do a lot of stop and go driving in traffic this afternoon and I noticed the car was idling kind of strange after I had been driving for a while. It never died but I can tell something is off all of a sudden. It's idling kind of choppy. Not really surging. I can only guess that it has something to do with the high temps outside. The car never ran hot though. Any ideas?

 

[jrichker]

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

 

[cdurbin]

I found the problem. I fired up the car and I once I got up close and really listened, I could here a faint whistling noise.
Turned out to be a vacuum leak. The hose that connects under the front of the upper intake had split right at the connection on the intake.
Replaced the hose with a temp fix until I can replace the whole thing this weekend. The headaches of a Fox DD. I've got to get me another vehicle...soon.

 

[cdurbin]

Looks to be the line to the charcoal canister. Do I need that line connected? I have the canister but all of the smog stuff has been removed.
I'm wondering if I can just cap that connection on the intake.

 

[mikestang63]

Leave it on. It vents gas from your gas tank. I know of guys that have removed it and left the hose hanging and then when they park it in the garage it smells of gas fumes. There really is no benefit in removing it IMO.

 

[cdurbin]

Leave it on. It vents gas from your gas tank. I know of guys that have removed it and left the hose hanging and then when they park it in the garage it smells of gas fumes. There really is no benefit in removing it IMO.

Good deal. I only ask because I simply replaced about a 6" section up next to the intake. I used a vacuum line coupling and some clamps.
I just did this as a temp fix though. I will go ahead and replace the entire line this weekend. Thanks