Just click the picture to watch the video. Basically, my car has had odd idle problems since I last had all my engine work done to it. Usually struggles to idle at all and dies when I first get on the road, even after warming it up for 10 minutes. Then after a while it starts to idle really high (around 1800 RPM) as I come to a stop, then after being stopped for about 4 seconds, idle drops back down to normal range. Sometimes when Im crusing, I dont even need to apply gas to keep my speed. So today I got home from work and pulled it into the garage, in nuetral with no gas pedal applied I was idling at 1800 RPM, usually it goes back down to normal idle range after a few seconds, but not at all today. Removed intake to check to see if throttle bade was stuck....nope not stuck, or open at all. I noticed that when I plugged that hole in the video, idle went back down to normal (800 RPM). Its been tuned (by a reputable tuner) quite a lot to try to get rid of this problem with no luck. Im just wondering if its anything I can fix....Any ideas?

 

What does the port you plugged with your finger go to? DBW/DBC? Is it the iac port. If it is maybe you have a lazy/failing one.

 

If it's DBC, I'm gonna say throttle cracker/follower needs to be looked at....along with the RAF tables. Also....what does "all my engine work" mean? Did you have a cam swap done?

 

Yeah pretty aggresive cam, heads, 90mm TB, LT's etc. What is DBC, and throttle cracker/ follower?

 

Yeah thats the IAC port Im pretty sure, the TB is mounted upside down for hood cclearance, that why its on the bottom

 

DBC being a cable throttle body and dbw being a electric tb. If you have a iac motor/circuit its dbc. I havent had the pleasure of any 4 bolt throttle bodys. But it sounds like your iac isnt doing its job , if its in the mechanical part or tuning idk. Just my opinion.

 

my guess, u either have an air leak some where OR u have a bad IAC

 

Yeah I used a cigar to find a couple vacc leaks arountd the TPS sensor and another on the Maggie itself. fixed them and rest the IAC/TPS sensors so well see if that works.

 

sounds like the IAC to me.
my car has been having the same issue except it always idles at 1100 rpms
sometimes it idles real high for a few seconds before it comes back down.
take it out, pull the plunger out, and leave it unplugged after you put it back.
crank the car and if it idles fine you know its the IAC
when you plug it back in itll idle back up if its bad