Idle Problem bouncy???

[Dr DSM]

My 92 talon tsi awd has been acting up lately. It started off dying whenever in neutral and decelerating. but now it starts up and idles high (like 2500rpms) and the check engine light comes on, then i drops down (1500rmps) then bounces between 1500 and 2000 rpms

talon idle problem - YouTube

this is a video of whats happening. at like 17 or 18 seconds i floor it and the rpms slowly rise

please help, im willing to try anything, i have a base idle set screw on the way. it may be a vaccum leak but i dont know. anything helps thanks

 

[agentorange313]

I would start by searching for other thread on this subject. Its been discussed countless times, idle surge.

http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html

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

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html

Since you have the stock ecu, I would reset my BISS screw, base idle setting, you have adjusted the BISS screw with a leak somewhere, you will need to follow these procedures after a boost leak test:
http://www.vfaq.com/mods/BISS-1G.html

http://www.plymouthlaser.com/biss.htm

 

[Nasty Dream]

Guaranteed it's the Idle Speed Controller (ISC), which is sometimes called the Idle Speed Servo, and at least one other name.

Replace it. If you need information on how to replace it, let me know.

EDIT: this should help

http://www.youtube.com/watch?v=l7R3gf7SiAo

This should help as well
http://www.youtube.com/watch?v=KibYz21IMA0

Well anyway, I had the same problem. Idle up and down in a loop. It can vary from time to time once it is bad. Sometimes the revs are much higher - like between 1k and 3k RPM, and it's really retarded and embarrassing at stop lights. Sometimes it goes away for a bit.


EDIT: OK, here found a better example, with a description:

http://youtu.be/7wwmiD8GYOg

If your idle starts bouncing after the car warms up and has a high rev it will be a bad (IAC) idle air control. This is in a 95 mitsubishi eclipse but is the same symptom on all vehicles with iac sensors. Easy to replace for a DIY kind of person but an expensive piece... $89.00 to fix it and it took me less than 10 min. to do. Afterwards if your check engine light turned on like mine did in the vid just disconnect both cables from battery turn the ignition to start pull key let sit for 30 min then reconnect battery if done right the check engine light will turn off and you wont void your warranty. If you erase code with obd2 scanner you may void factory or any extended warranties you may have had. Just fyi.

 

[Dr DSM]

ok cool. thanks guys i'll let you know when its fixed

i checked the isc and all coils were good, so looked at all the lines and found the pcv piping was cracked. I think thats the problem and im getting a new pcv with the piping and hopefully that fixes it. what do you guys think?