Car Cut Off , Ignition Switch ?

Does it die after sitting in idle at a intersection for a bit, or die as you're decelerating to the intersection?

run the codes- could be IAC, MAF, TPS

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 134,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

Do jrichker's method. I would also recommend doing a full tune up on the car (Air Filter, Oil, Spark Plugs & Wires, etc...). Take apart the intake and clean the MAF Sensor off with MAF cleaner at your parts shop. I don't know if electrical cleaner will damage the MAF.

Also, if you have an AOD, replace the transmission oil filter and look in the oil for metal shavings or burnt fluid. If it is clean and not burnt you should be good.

Best thing to do is run codes and fix the surging idle with jrichker's method. The first thing I did when I got my fox was a complete tune-up

Even though your check engine light may not be on it, the computer could still be throwing codes. Just tackle one thing at a time. What sensor are you talking about? The MAF? Its easy to clean, just take it off and spray it with the cleaner. Make sure you get the tiny wire that actually takes the oxygen flow ratings.

http://www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW

I got this one, works like a charm and its only $22. Has a digital reading and comes with a book that explains the codes.

Killa said:

thanks that pretty cheap and handy, just order 1

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Np, glad to help when I can . The plug you use is in the driver's side engine bay near the firewall. There will be a big connector with I think 3 wires and a small connector with 1 wire. You need to plug both of them into the code reader. Jrichker has a picture of it in the surging idle checklist thread.

Clean your MAF and IAC. sometimes those can be the culprits. Also check your vacuum lines for cracks.

@Killa There's a way to dump the codes and tell with a test light in the diagnostic plug. That's the easiest/cheapest way I've seen, and Im 99% sure that @jrichker 's post had that info in it. I am really curious to see what the problem is because my first car had those same issues and unfortunately I was forced to sell it before I could fix it properly. (story for another day.)


But out of plain curiousity (and I mean no offense by asking) what is your first language? I am semi-fluent with Spanish, so I struggle with communication in another language daily with my tradesman. What did you find was the easiest way to learn? I try and listen to conversations and I pick up new stuff every day, but they speak too fast! Thanks!

hoopty5.0 said:

@Killa There's a way to dump the codes and tell with a test light in the diagnostic plug. That's the easiest/cheapest way I've seen, and Im 99% sure that @jrichker 's post had that info in it. I am really curious to see what the problem is because my first car had those same issues and unfortunately I was forced to sell it before I could fix it properly. (story for another day.)


But out of plain curiousity (and I mean no offense by asking) what is your first language? I am semi-fluent with Spanish, so I struggle with communication in another language daily with my tradesman. What did you find was the easiest way to learn? I try and listen to conversations and I pick up new stuff every day, but they speak too fast! Thanks!

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You are correct; all the how to dump codes and a bunch of other helpful hints are in the Surging Idle Checklist .
My guess is that Killa isn't looking for diagnostic help, he wants someone to tell him what magic part to buy to fix his problem.

I will exercise restraint from making snide remarks about his grammar. However, I will get out my structured troubleshooting stick and beat my drum and him with it at the same time...



Sir Joshua Reynolds' famous quotation: "There is no expedient to which a man will not resort to avoid the real labor of thinking."

Good troubleshooting takes time. Everyone seems to be looking for the magic tip that says replace this $13 part and your problems are cured. You don't have to think, dig or diagnose, just buy the part and install it. Unfortunately, it doesn’t work that way 99% of the time.
Thinking is hard work and educated thinking requires much more effort than simple parts swapping. The complexity and age of these 5.0 Mustangs works against that, as well as the number of hands that have “modified” the original design. Sometimes that modification is well done with good workmanship and other times it is mechanical road kill. It is very easy to become the victim of the previous owner’s efforts.

I spend a great deal of time trying to communicate the methodology of structured troubleshooting principles. For those who haven’t been beaten with this stick before, here they are again:

1.) Understand the system. That involves reading some books to get an overall picture of how it works. For 5.0 Mustangs, that list starts with the Chilton shop manual and the Probst book, Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.
It's about $32-$45 new, a used copy will be about $20+, see http://www.amazon.com. Select books and then select search. Use the full name or SBN number (without dashes or spaces) to do a search. Use the ISBN number and your local library can get you a loaner copy for free for 2 weeks or so.

For free automotive electrical training, see http://www.autoshop101.com/ . I have personally reviewed the material and it is very good.
Another resource is the following website by Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring: http://www.veryuseful.com/mustang/tech/engine. Study the diagrams and tech articles. There is an amazing amount of good stuff in one place for FREE.

2.) Isolate the problem. You need to be able to break the system down into functional blocks or subsystems. Once you know what subsystem has failed, it is much easier to troubleshoot. Group problem symptoms according to what system controls them.
Don’t look for a fix for ignition problems by adjusting the fuel pressure. Have an organized, step by step, approach to work your way through a subsystem before you quit and go off wildly chasing rabbits. You have three tools to use in your efforts: measure, observe and think!. Use these three tools to narrow down the list of possible failure points into a small, easily managed list of items.

3.) Install the fix. Now that you have a short list of suspected villains, plan your repair efforts so that you do the easy things first. If an item from the easy list didn’t fix your problem, then look at the high failure rate items. Spend some time here on Stangnet and you’ll get an idea of what the most commonly replaced parts are, things like TFI modules, PIP sensors, ignition switches and fuel pumps.

If you make a change and it doesn’t relieve the problem symptoms, put it back the way it was. I have a stack of parts from where I swapped a part and it didn’t fix the problem. I put the old part back on the car and the new part went on the shelf. Someday I will either
use them or trade them for something else.

Killa said:

engine and transmission rebuild 20130 miles ago, I think it sensor, cause everything else look new accept sensor. so ignition switch have nothing to do with surging and cut off right ?

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Which sensors?