Hi all,
I have a 1998 SW2 with 178,000 miles on it. Recently the engine started racing upon start up, when shifting gears (It's a manual transmission), and when coasting to a stop. Only when I come to a complete stop does the idle return to a normal rpm of 1,000 to 1,100. Also, the colder it is outside, the higher the rpm when racing. I can't find any vacuum leaks or loose wires and the check engine light is not on. An engine scan does not provide any codes. Any ideas?
Thanks a bunch

 

First clean the throttlebody INSIDE and OUT

 

indeed clean throttle body first.....

1k to 1.1K is kinda high for idle, especially for a manual DOHC -- mine idle at about 850...

let us know how throttle body cleaning goes....

 

That would have been too easy!!! I forgot to mention in the original post that I had cleaned and lubed the throttle assembly. I even checked to see if my accelerator pedal was sticking. Today I did a lot of coasting, down hills, up to stop lights, etc. In the morning and this evening when the temp was lower, the rpm's went to about 2,200 until I came to a complete stop. Then it went to 1,100. In the warmer part of the day, the RPM was around 1,900 when moving. I also eased my foot off the clutch without touching the gas. As soon as the car started moving, the rpm shot up. I do most of the work on this car and I'm baffled.

 

IAC

Remove throttle body clean in and out along with the Idle Air Control

 

damn you stole my suggestion to be.....

 

Possible Vacuum leak? Check all hoses around MAF. With that many miles, a split or cracked rubber hose could definitely cause it. Also, Take a water bottle, With engine running, and spray it along the intake to head mating surface- if idle subsides; then you've found your vacuum leak. Hope that might help you.

 

and sucked water into the cylinders. please don't use water

 

ok. Use gas? lol.
Water is fine. Or use any suitable sub (liquid) that youre comfortable with.

 

Clarification: Normally it would be a hose anyway. Or an intake leak; using water would simply suck in to lifter valley anyway.