Idle surging

[Busa45]

I have a 2002 with 23K miles. Lately, from time to time the idle does not come back down to set point after decelleration. And, sometimes while sitting at a light, the idle will increase up to 1500-1800 rpm on its own then drop down.

I checked the cable adjustments, vacuum hoses and elect connectors. Can't seem to find anything. Took it to my shop and they said it sounded like a vacuum leak somewhere. But, after I left there it was okay until yesterday after driving a while, it would not idle back down below 2000 rpm for a while, then okay again.

I would think if it's a vacuum leak, it would be doing this all the time. I'm thinking a sensor going bad? Put a jumper in the diagonostic plug but there were not fualt codes and throttle position sensor indicates it's okay.

Anyone have a similar problem or any ideas?

Thanks,

 

[Mr Bogus]

assuming all the previous checks were done and things were fine..

pull the airbox and look down the throttle bodies.. (maybe a bunch of coking or gunk build up?)

you can take some "carb clean" and with the motor running start giving short shots around the bases of the throttle bodies and all the manifolds and if there is an vacuum leak, you should be able to hear the motor respond.

could also be the manifold air temp sensor going south.. if you could perhaps tie the issue down to temp outside?

 

[Busa45]

FYI, looks like I got it fixed. Yep, rolled the dice and spent $40 on a new inlet air temp sensor. Wow, runs like a new bike. No more problems so far.

Thanks,
Busa 45.