I stop at a light or at a stop sign it starts having bouncy RPM's?

DBAUM

MEMBER
1996 FORD TAURUS
6 CYL
FWD
AUTOMATIC
121,000 MILES

I have the car listed above GL. 3.0 Liter engine V6. My problem started about a year ago intermittently and has gotten worse. First start of the day it starts right up stalls and then I restart it and it stays running and runs fine. Car runs fine while driving but as soon as I stop at a light or at a stop sign it starts having bouncy RPM's (like up and down up and down). Sometimes it fixes itself and sometimes it drops so low the car stalls and I can restart it fine. If I can catch it in time I can usually throw it in park really quick and it kicks up the idle or RPM's to that of a parked running vehicle and it stays running fine with no problems. Catalytic Converters were checked and the rear one was plugged solid and both were replaced but car still does the same thing. Any suggestions.

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like you might have an issue with the idle air control valve (IAC).
The IAC is located on the side of the throttle body.

Many times a dirty IAC will trigger an issue with the idle quality.
As air travels thru the IAC the larger air particles get stuck to the inside of the valve. Overtime it will have enough buildup to impact the idle.
You might be able to service the IAC by cleaning it out. Typically that will fix the issue.

https://www.2carpros.com/articles/how-a-idle-air-control-valve-works
https://www.2carpros.com/articles/idle-air-control-valve-service
https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

I have attached diagrams for your reference.

Please let me know of any questions.

Thank you.

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