93 5.0 Lx Stalls In The Summer

Ryu

Member
Jun 22, 2015
37
2
8
TL;DR Car stalls only on hot days (around 90°) usually after i turn it off and try to turn it back on and after i was driving for awhile, with two exceptions it has stalled while driving.

My car has stalled in these scenarios:

1. My car stalled while driving on the freeway while it was 80° after driving 35 miles. If i remember correctly the car starts to shake at the back of the car and loses power and i had to pull off on the side of the road wait 15 min and i started it back up and drove the rest of the day fine.

2. I drove 10 miles while it was 90°, stopped for 5 min, drove another 5 miles to sonic ordered a drink waited 15 min turned on car was able to back up 8ft but then started to sputter and while sputtering got to another stall that sonic has and waited 20 min and was able to get home.

3. When it was 90°-100° I drove 90 miles non stop on the freeway I got to my destination, turned off my car and let it sit for 20 min. I started it back up drove another mile turned it off tried to start it and it stalled. I waited 15min tried to start, engine idles at 500- rpms for 3 seconds then it stalls. Waited another 25 min, engine idles at 500- rpms for 3 seconds then it stalls again. Waited another 30 min finally started. (When the engine idles at 500- rpms it sputters and stalls).

4. Next day at 4pm still 100°+, drove 50 miles, went to get gas, turned on my car, got to the intersection and the engine stalled at the red light (all within 20 yards). same thing where the engine starts to idles at 500- rpms for 3 seconds then it stalls. I turned off the car and waited for the light to turn green turned on the car and before it had a chance to stall i revved the engine up to 3500rpm, got out of the intersection and drove another 40 miles home no problem.

5. Another time when my engine stalled at an intersection i drove 20 miles to my destination and drove another 20 miles back, got to an intersection and the engine stalled while at idle.I turned off the car and waited for the light to turn green turned on the car and before it had a chance to stall i revved the engine and got out of the intersection

Other things - I don't think the engine is overheating unless my gauge is lying to me because it has never gotten above half. It it had been sitting in a garage for 7 years, replaced the fuel pump, gas tank, TFI, coil, fuel injection system. Also after doing my own research I thought it was vapor lock or the gas cap was creating a vacuum in the gas tank, the fuel filter was another suspect. Other names that came up was the EGR ,ignition control module, IAC valve. If it is any of these are the problem or something else, any directions would be most appreciated.
 
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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. 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.
 
You can check the codes but sometimes a bad ECT sensor will not set a code. I don't know if that's your problem but it was my problem just last week.