Help with Idle

[CNTW84U]

Today my idle started to act up. At a stop light
it would not go below 2,000 rpm's for several seconds.
Then it dropped to 1,200-1,500 and then to 750.
It even stayed high during the shift from 1st to 2nd.
What is causing this to happen?
Bob

 

[genXgts]

Mine has a similar situation after a hard run only.

At the light try blipping the throttle as if kicking the choke off on an old car. Mine will settle down from 2000 down to 750, after a cool down run it settles in where it should be but needs a few blippings on occasion.

 

[JimDavis MT 97GTS 650R]

CNTW84U: Sorry to say, this behavior is "the nature of the beast". Your computer has a built in program which drops the throttle idle in 2 stages to provide smooth shifting and better emissions. The system stinks IMO but you can't defeat it. It is a non delete part of the engine's computer programming. You might do a "topic search" on "hanging idle". There are some other related issues, although unlikely, that might cause this problem. Disconnecting and reconnecting the battery will temporarily stop the problem, only to have it return as soon as the computer relearns the idle program in a few miles. To the best of my knowledge, there is no permanent fix. Anyone els got something to offer?

 

[kowalski vanishing point]

Use the "Search" feature
and type in "idle hang" and you'll find all permutations
of this maddening problem.

My Viper almost did not pass Smog here in Cali
because the idle stayed up at 1200 rpm.
Fortunately it dropped down to a more normal idle just as the tech
was about to fail it.

The only advice I haven't tried is "have the Viper tech reflash your PCM". Hopefully that will work.