RPMs all over the place?

[menuserve]

i'm not sure why buy my idle RPMs really vary...

on the way to work at a light they seem to bounce up and down between 500 and 1000...
then sometimes at a light it will be sitting around 1800 or so....
and then every now and then it appears normal and steady around 1100 or so.

what could be the cause of this?

 

[Daedalus]

http://www.nsxprime.com/forums/showthread.php?t=25019

Dirty throttle body seems to be the first thing that comes to the minds of experts here.

 

[scorp965]

I had a similar problem on a BMW, it ended up being a faulty ICV (idle control valve) - could also be a vacuum leak, etc.

 

[menuserve]

are there instructions on cleaning the throttle body or does it have to be done by a shop?

 

[Larry Bastanza]

This is not the classic symptom of a dirty throttle body. You have air entering the system due to a faulty idle speed control or vacuum leak would be my guess.

HTH,
LarryB

 

[lowdwnsteve]

I had the same problem- this is how I fixed it...bought a bottle of throttle body cleaner-- sprayed all over inside the TB. started the car up - revved it a little.. had a friend sit in and keep it around 2k RPM and sprayed all over inside TB again..... start there..

 

[menuserve]

I had the same problem- this is how I fixed it...bought a bottle of throttle body cleaner-- sprayed all over inside the TB. started the car up - revved it a little.. had a friend sit in and keep it around 2k RPM and sprayed all over inside TB again..... start there..

what kind of throttle body cleaner? something i can get at the local auto parts store?

 

[710]

To find a leak, get some starter spray (starter fluid?). Start the engine, let it idle. Spray the starter fluid all around the outside of the inlet track (throttle body, inlet manifold etc). Try different places.
Spray some into the air box where the filter is to get an idea of what you are looking for.
If there is a leak, hopefully some starter fluid will get sucked into the leak and into the engine.
If that happens the rpm will momentarily rise. Then you know where the leak is.
peter

 

[SilverStone05]

i'm not sure why buy my idle RPMs really vary...

on the way to work at a light they seem to bounce up and down between 500 and 1000...
then sometimes at a light it will be sitting around 1800 or so....
and then every now and then it appears normal and steady around 1100 or so.

what could be the cause of this?

Just FYI...after the car is warm, idling at 1100 is not normal. Should be below 1000 :smile: