rough idle

[Brian Kirton]

My 2005 ST has a rough idle from time to time. Seems to happen more on cold days. It seems like the engine is running low rpms like a choke isn't operating. Took it to a local garage for maintenance and they didn't observe the problem and the computer showed no misfires. The truck seems to operate just fine during driving but I thing the mileage could be better. I bought the truck used and have used only 87 gas. Ran one bottle of injector cleaner w/ one tank of 97 octane. I was wondering if the computer may have gotten "off" by the previous owner using E-85. Any suggestions?

 

[Tom Schindler]

Clean or replace the ISC Valve.





Tom

 

[Brad Byrd]

B K: check the member projects regarding the Sea-Foam treatment... step by step with pictures... easy to follow. You can buy the sea-foam at wal-mart-- advance auto parts... etc... $6.00. Last week my engine light came on--- codes were indicating that both o2 sensors were bad----- got some seafoam- ran it through a vacuum line ---- unhook battery cable to turn light off---- hasn't come back on yet---- and the trac idles soo much smoother now- didn't realize how rough it was before until i used the sea-foam... just my 2 cents worth........ Brad

 

[Rodger Tellefson]

Cayman, That's the IAC motor.



bk, Here's the link to the project on how to clean it.