car stall when coming to a stop

[f8tlfiveo]

i just put a new speedometer cable and a vss sensor in for my maf swap about 2 weeks ago...drove the car for 2 weeks before i changed the computer and everything over...the car would sometimes almost come to a stall when coming to a fast stop until i put the vss and cable in....this weekend i finished up the maf install everything is working fine but now it wants to stall again when you are coming to a stop...i think it is idiling pretty low (about 630 rpms) before i did the swap it idled at about 780-820 and it was fine...i have a new iac valve..so i am going to turn the idle up a bit and recheck the tps sensor.....any help would be greatly appreciated...thanks

 

[f8tlfiveo]

just went out and turned the idle up to about 900-950 and turned the timing back to 13 deg..seems like it running alot better. Does anyone know if the mass air make a difference over the speed density from just swapping over just the mass air?

 

[Mustang5L5]

Did you tie the MA computer into the VSS wiring? I beleive you have to tap 3 wires into the driver's side footwell to do this.

Just hooking the VSS up will not achieve this.

 

[TenorPlayinGuy]

^^ Agreed, you have to tap into some relays and such. I remember that part. Then run them over to pins on the EEC connector.

Interactive Systems & Technologies Mass Air Home Page has a kit for this I believe.

 

[f8tlfiveo]

all those wires for the vss and the fuel relay thing under the seat are hooked up, i think after i did the mass air conversion it lowered my idle a little, i have been driving around all day and after driving the car for a while the idle is down to about 780-800 which is right where it was before i did the conversion. so the car is running great now and it doesent want to stall when i come to a stop anymore. i followed the instructions that i got from stangnet too a tee, soldered all the wires and did the vss and the fuel relay thing that way if somthing wasnt right i knew it wasnt going to be either of those cause i triple checked them.

 

[jrichker]

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.