Minor Cold Start Idle Surge

John Dirks Jr

there is enough sticking out to grab on to
5 Year Member
Jun 28, 2013
With my recent V3 install there are two minor things left to sift out. Belt walking and I'm on that, and an idle surge on cold start up.

The idle will surge on cold start for the first 2 or 3 minutes of run time and then it clears itself up. I can watch the wideband o2 and here's what happens. The mixture gradually leans out (bigtime), then just at the point where it's about to stall, it shoots over tho the rich side and the idle surges back up. Like I said, 2-3 muintes it will clear up and hold steady idle at 14.5 AF. After the initial surging clears itself up, everything is fine. This never happened prior to the V3 install which included a custom tuned chip, 30lb inj and a calibrated MAF.

It's not the end of the world but if I can track it down, that would be nice. What could it be?
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SN Certified Technician
Mar 10, 2000
Dublin GA
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. It includes how to dump the computer codes quickly and simply as one of the first steps. 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. :D

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.

John Dirks Jr

there is enough sticking out to grab on to
5 Year Member
Jun 28, 2013
J, I promise I'll give the list a shot. I'll let you know what I find. Thanks for putting it together.
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