Mustang Stall / Shut Off When Gearing Down to Stop

[Manewaymja2]

Hi there
My 87 Stang Recently Started to stall when ever i gear down from say 5th - 4th -3rd etc in order to come to a complete stop. At that point she would stall (trying to recover surging idle and sometimes cut off completely) unless i press gas peddle to rev motor and to catch idle before shuting down.

This problem never occured when she was SD only after the MAF conversion.

Any advice could realy help me.

Thanks Matt

 

[87coupe50]

Check the codes and see if you got a 14 (I believe). The stator in the distributor could be going bad. Had that happen on my car.

something different: when it stalls, do you have to press the gas pedal in all the way before it will restart?

 

[ID89GT]

How old is the fuel filter

 

[HISSIN50]

Is the VSS connected and functional?
Is your IAC functional?

 

[Manewaymja2]

No Code 14

will Change Fuel Filter

What is the VSS and where is it located?
Just Changed the IAC/Its good.

I did get a codes related to EGR so im going to change that as well.

 

[jrichker]

The VSS is the Vehicle Speed Sensor, and it is mounted on the speedometer cable where is plugs into the transmission. If it goes bad, you usually get a code 27 or 29.

See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[Mustang5L5]

More than likely that is the issue. The car was converted to MA and the wiring was never tapped into the VSS sensor.

Basically the Vehicle Speed Sensor tells the computer when the car is coming to a stop to prevent this stalling.

If your 87 has cruise control, you already have a VSS. You need to tap into two wires in the driver's footwell and repin it into the EEC

If your '87 does not have cruise control, you will need to purchase a VSS and a new speedo cable for a VSS and install those and THEN do the wiring changes.

I don't have a link to the wiring, but if you search around for mass air conversion threads, there is more than likely a link posted

 

[Manewaymja2]

My Car does have cruise Controll and i did tap into the two wires by the drivers side firewall area by clutch and taped into ECU like the online instructions said. Could it be that the VSS has just gone Bad?

 

[brecht63]

IAC- Had the same problem on a couple of 302's, try setting you base idle around 1000rpm and see if it still does it, if not its more than likely your IAC. Could be your base idle not set high enough too? Electrical could check out ok but it may be stuck shut. just my 2 cents

Sorry, missed where you said you changed the IAC.

 

[Strype]

do you have a cold air intake. Fan Turbulence will screw with maf
Posted via Mobile Device

 

[Manewaymja2]

Yes i Have a Cold Air Intake.

What do you think my Base Idle should be at?

I think Ill change the IAC as its a aftermarket one, could be faulty, will try to get factory one from FORD.