Stalling On Cold Start

91FoxGT

New Member
Jan 13, 2017
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I've got a '91 5.0 with about 130,xxx miles and about 2 weeks ago it started having trouble on a cold start/idle (dropping to ~200 and almost stalling before bringing it back up), and idle RPM's are sporadic (moves between 600~800). I replaced Distributor Cap, rotor, spark plugs, and wires and it didn't help. Cleaned old IAC Valve, didn't work. Replaced old IAC valve last night, and this morning car actually stalled for the first time (had to gas her to keep her alive), so i don't think that helped either haha.. Once warmed up, car rides fine, starts fine, but still idles a bit uneven. I've read that the ECT Sensor may cause this, but the car doesn't overheat ever. The temp guage never even gets above the middle line, even when running it hard. Fuel Pump does whine like a mother-father, and i've read that can cause stalling itself, but not the low/sporadic idle i've been getting. I never run the car under a half tank of gas.

Only mods on car are cone filter, and BAMA tuning chip. These were done months ago and I don't believe they're part of the problem. Any help would be appreciated.
 
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Check codes even if the light isn't on, perform the surging idle checklist that jrichter has. Do a search here for it. Follow it in order, step by step. Don't skip or assume it isn't a necessary check.

Also, I don't have any experience with the BAMA chip, but it may be causing you some issues.
 
Check codes even if the light isn't on, perform the surging idle checklist that jrichter has. Do a search here for it. Follow it in order, step by step. Don't skip or assume it isn't a necessary check.

Also, I don't have any experience with the BAMA chip, but it may be causing you some issues.

Ok i just searched up that name and found a bunch of people with the same problem. Will check on those threads. Sorry for yet another repost of the same problem. Thanks for the help
 
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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 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.