Idle Surge or Something Else?

[LxiMax]

Ok, I've had idle issues with this car ever since I got it, which have not been bad. Just a little sputter at idle, almost like a misifre. Now recently, after driving it for a while, ill stop and put it into Park and it will start from 900rpm then climb as high as 1500rpm then slowly climb down to 1200rpm. I'll give it some gas and then it will come back down to 1200rpm. It almost feels like a little gas is being given but a full idle adjustment was just done, properly at that. ( Fixed Stop Screw, TPS adjustment, throttle cable adjustment. Didn't mess with the BISS screw. ) I'm thinking maybe the FIAV is becoming faulty? Any help is appreciated. Oh, car is a 95 Auto GST.

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)


this is a great place to start, good reading could be any of the things posted in the list.

 

[eagle93tsi]

Next thing to consider doing is a boost leak test.

http://www.dsmtuners.com/forums/art...st-how-boostpro-net-tester.html#post152554139

 

[LxiMax]

Well I've boost leak tested before ( didn't find any leaks ) but never done it with the soapy water method. Also I plan on replacing practically any seal or gasket I can just for peace of mind. Im also going to pick up a rebuilt throttle body from throttlebodys.com. Seems like the consensus is that they're the place to go for rebuilds.

 

[luv2rallye]

Are you sure the IPS (Idle Position Switch) is adjusted properly? If not the ECU may never try to adjust idle because it thinks the throttle plate is not closed (so it lets it do whatever it wants).
http://www.dsmtuners.com/forums/newbie-forum/255885-bad-tps-again.html#post151940336