Car dies randomly at idle

Stanger007 · Jun 1, 2005

Ok after doing a search, I was unable to find any solutions to the problem I'm having.

My car usually dies at a redlight idling about once a week - today it did it twice. Also about once a week right after I start it and put it in reverse and give it gas, the RPMs will drop real low acting like it wants to die and then surge back up. About every third time the car will die instead of surging back up. I smell rich gas fumes when it starts again.

The symptoms are this: I will be sitting at a stoplight and the car is idling rock steady at about 650rpm and all of a sudden it is like someone turns the key off - no bucking at all, it just dies. I can put the car in neutral (autotragic) and it cranks right back up with no problems.

I have on new o2s, no vaccum leaks that I can find, new PCV/screen/grommet, timing is set at 14* (running 93 octane), no CE light or codes, new plugs (gapped at .054), wires, cap rotor, air filter, fuel filter, new MSD coil, new ECT and IAT (sensor in intake tract). Just cleaned MAF and IAC. Even put in fresh, new halogen fluid!!! Car has 119k miles on it.

Any ideas what to check next?

Yellow302 · Jun 2, 2005

I have similar problems.. i will tell you right now that if you tried everything else, dont expect many responses from 5sp guys. I have simalar symptoms with my AODE. 98k mi

If my car is hot and i fill up at a gas station, I'll start the car and it will idel high... drop into gear and gerge like hell. I dont know what it is any more.

Our AODE runs off of TPS and Maf bull ****. Once I have changed them and a few other mods everything has gotten worse. I cleaned my maf and thought that everything was good and it starting all over again.

I wish we had an AODE guru here because I know its alrelated to that damn thing... I dont want to drive stick but with this car I just dont know some times.

super302 · Jun 2, 2005

So far I have the common items that cause most problems:
1.) Dirty or defective IAB (or IAC) - clean or replace IAB
2.) Defective TPS - replace TPS
3.) Vacuum leaks - locate & replace leaky gaskets & hoses.
4.) Bad O2 sensors or bad or missing O2 sensor ground - replace o2 sensors and check ground. The ground comes out of the fuel injection wiring harness & is a orange wire with a ring terminal on it
5.) Insufficient voltage at idle - reduce electrical load, replace or upgrade alternator.
6.) Dirty 10 pin wiring connectors or damaged wiring going to/from the 10 pin salt & pepper shaker wiring connectors.
7.) Dirty or defective MAF element. Clean or replace the MAF element
8.) MAF meter on CAI system that needs clocking or protection from engine compartment air turbulence. Make of CAI & MAF meter is very helpful info, so please include it if this is your problem

wytstang · Jun 2, 2005

Sound fuel related how thefuel pressure at idle?

Stanger007 · Jun 2, 2005

Thanks for the responses, there's a few things I haven't check/replaced in there!

No idea what the fuel pressure is at idle. What should I be looking for?

Speaking of, where can I get a good price on a decent guage?

stack · Jun 2, 2005

It just so happens that I was at Advance auto today and while I was waiting form my parts from the parts guy I was watching the TVs that they have there. There was one of those multiple choice questions that came up and it was what were the symtoms of a faulty or dirty MAF meter.

A. Stalling
B. Hesitation
C. Poor fuel economy and rich smelling exhaust
D. All of the above

Well the answer was D so my guess is the MAF meter is either not working or really dirty

hope this helps

stack

mo_dingo · Jun 2, 2005

Start with simple stuff. Check fuel pressure, get a vacuum gauge and check your vacuum at idle.

These sporadic problems are extremely difficult to diagnose until they get worse, to the point you can reproduce them on a whim.

Until then, good luck. My guess, being as it's an extremely intermittent problem, is a bad electrical connecton at one of the sensors, fuel pump, ignition, etc.

Let it get worse, and then you can troubleshoot it.
Scott

Stanger007 · Jun 3, 2005

I had an epiphany this morning while thinking over some of the issues I had with my 90 5.0.

Battery cables. My negative cables doesn't tighten all the way b/c the clamp is corroded. The cable inside may be corroded as well. Since I run underdrives, at idle which is 650rpm for me the juice flowing through the cable is not a whole lot - could be causing my issue?

Anyone know the exact replacement length for a negative battery cable?

Stang35 · Jun 3, 2005

Check the IAC valve, mine would sputter and carry on for a while and occasionally die, then a couple of days ago it would not run unless there was rpm's building in the motor, take it off, and spray a good bit of carb cleaner into it and let dry, i had to use nearly a half bottle cleaning it, then put it on and take your battery cable off and put it back on because after i did it my check engine light came on but after i took the batt off it stopped.

Stanger007 · Jun 3, 2005

Allright, I may try that again (did it about a month ago). Is it buildup in the IAC that causes it to malfunction or the electronics going out or both?

I may just bite the bullet and buy a new one in the future since I've been replacing sensors and things one at a time (119k miles) and plan to keep this car for a while longer since it is in such great shape.

Stang35 · Jun 3, 2005

On mine it was just a build-up, and so far it is running fine but you never know it could be the elecs in yours. a new one is right around $59 i think, so not too bad, but worth trying to fix the old one first.

Stanger007 · Jun 4, 2005

Put my new negative cable in today and took it for a test drive. Cranking time to start the car is less and throttle response is better. It didn't die in the half hour I drove, but I'll keep ya posted as the week progresses since this is such an intermittant problem.

For futuer searchers, the proper length on a negative battery cable is 54". make sure your cable has an extra smaller wire at the battery end of it that you can crimp to the harness the mustang uses.

Stanger007 · Jun 7, 2005

Ok, new cable did nothing for me.

Car still dies although it hasn't died nearly as much. I *may* be able to reproduce the dying however.

It seems to die more with accessories on at idle. I was able to make it die once by idling w/ lights, cd player, wipers etc on. I don't mind pulling off the ASP alternator pully and replacing it with the stock pully, but I don't want to band-aid a problem either. What else can I check/replace to see if the lack of power at idle is causing my car to die?

It seems like I'm getting close!

Stanger007 · Jun 13, 2005

UPDATE

Replaced old distributor with a new one and went over all the vaccum lines that I could find but but car is still dying randomly when I put it in Reverse.

I have a BBK 255 fuel pump and a fuel gauge on the way.

Synned · Jun 13, 2005

My car dies every time if I start it up and quickly put it into reverse. If I wait a couple of seconds it doesn't stall, so I don't think our problems are related.

Stanger007 · Jun 19, 2005

***UPDATE***
Put in the pump and gauge today. When I first started up the car it was running at 34 and when I got to the gas station to fill up (had 1gal in tank) it was still at 34. Got home and it was sitting right on 38. Had to unplug the battery to put the pump in so computer is relearning, but car running great thus far.

I also have a new IAC sitting here to put on if the problem isn't corrected.

Stanger007 · Jun 21, 2005

Aaak car ran great for two days then today it died on me twice going into reverse from a parking spot and then twice trying to get it into drive.

I have a new IAC to put in - guess I'll handle up on that tonite. I'm running out of sensors and such to replace.

What else can I check???

DoHcHoLlIdAy01 · Jun 21, 2005

Stanger007 said:
Aaak car ran great for two days then today it died on me twice going into reverse from a parking spot and then twice trying to get it into drive.

I have a new IAC to put in - guess I'll handle up on that tonite. I'm running out of sensors and such to replace.

What else can I check???

I had the same problems with my 95 GTS. I think this is a pretty common problem with 94-95 mustang GT's. Having a custom chip burned will help a lot with the idle problems, if there is nothing else wrong with the car.

Stanger007 · Jun 21, 2005

DoHcHoLlIdAy01 said:
Having a custom chip burned will help a lot with the idle problems, if there is nothing else wrong with the car.

So what is the chip changing in the EEC?

My car isn't very far at all from stock - surely I've got a sensor or something going out or giving the EEC a bad reading and causing it to randomly die. It seems like it is more apt to die when it is a hot start and I put it in gear.

I ordered two books on tuning the EEC today - I plan on getting a twEECer RT in the future for mods - maybe I can get some info out of the books on testing the various sensors.

DoHcHoLlIdAy01 · Jun 21, 2005

Stanger007 said:
So what is the chip changing in the EEC?

My car isn't very far at all from stock - surely I've got a sensor or something going out or giving the EEC a bad reading and causing it to randomly die. It seems like it is more apt to die when it is a hot start and I put it in gear.

I ordered two books on tuning the EEC today - I plan on getting a twEECer RT in the future for mods - maybe I can get some info out of the books on testing the various sensors.

I would let a professional do the tune on your car. I had the exact same problem on my 1995. Runs and idles fine when cold, but when started hot car runs like crap and the idle dies often. I also used to get a lot of pinging. I must have changed almost every sensor on that thing and still nothing changed. I would just ask a custum tuner if they can help you with the common 94 95 problems. You can just live with the problem or just drive it in the winter. WHat sensors have you changed? Did you spray the IAT sensor and the MAF sensor with carb cleaner. A lot of times if you run a K&N filter, the oil on it can get all over the IAT sensor and the MAF Sensor causing a bad reading to the CPU. Let me know what you have done in way of the sensors and other things to fix the problem.

Car dies randomly at idle

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