Car Sputters/stalls when slowing down

[1988_gt_mustang]

Well this just started happening b4 i put it away for the winter but now im gettin eady to pull it back out and need to get that fixed. When u start to slow down from any speed the idle drops way down the car sputters and once and a while stalls. Havent replaced anyhting yet but u think its the fuel filter?

 

[TENGRAM]

Well this just started happening b4 i put it away for the winter but now im gettin eady to pull it back out and need to get that fixed. When u start to slow down from any speed the idle drops way down the car sputters and once and a while stalls. Havent replaced anyhting yet but u think its the fuel filter?

2 possibilities,
1. vehicle speed sensor - this is located at the end of your speedo cable, where it meets your transmission. when you begin to slow down this sensor is responsible for noticing and sending a message for the idle air bypass to open fully, to keep the car from stalling.
2. idle air bypass - if its stuck closed, you will experience the stalling you mentioned and a rough idle.

make sure the vss is wired up(mine wasnt)
remove IAB and clean with carb cleaner to remove the carbon that has built up in there, or replace it.

 

[04-SVT]

Im willing to bet its the IAC valve. I had the same symptoms. I cleaned it out with WD-40 and brake wash. I also made sure the throttle body hole/port was also clean. I also used WD-40 on that, fixed my problem
Make sure you dont have any vacuum leaks

 

[jrichker]

See the sticky "Help me create the Surging Idle Checklist" at the top of the forum for help with your idle problems. The first post in the sticky has almost all the details you need.

 

[TENGRAM]

Im willing to bet its the IAC valve. I had the same symptoms. I cleaned it out with WD-40 and brake wash. I also made sure the throttle body hole/port was also clean. I also used WD-40 on that, fixed my problem
Make sure you dont have any vacuum leaks

use carb cleaner instead. the wd40 attracts dirt and it will gum up a lot quicker

 

[1988_gt_mustang]

thanks fer the help