What to look at next?

[swanny]

I've read through the "fixing an erratic idle" article a few times but upon further research I have dug up a couple other possibilites for the cause of the RPM's shooting from 800-3000 at idle and I need some educated guesses for what to check next and if there is any way to test them.
-I replaced the IACV, did nothing.
-Looked for vaccum leaks, found none.
The other possible causes I have found in researching are the FITV, TPS, and also the O2 sensor. I know to test the TPS can be tested with a voltmeter and I believe it is supposed to read .5 volts at idle and 4.5ish at WOT (correct me if I'm wrong) Is there any way to test the FITV or the O2 sensor? This is on a 95 GSR.
Thanks.

 

[nfn15037]

Almost without a doubt its the FITV. Try plugging the port inside the TB that is upstream of the throttle plate with your finger and see if the surging stops. If so, take it off the bottom of the TB and see inside, the plunger has probably come unscrewed and is causing a severe vac leak.

 

[HatchSpeeD]

What is the FITV?

 

[swanny]

Fast Idle Thermo Valve,