bouncing idle *UPDATE-Problem solved!!*
 

Okay, I've spent the last 2 nights reading archived posts and threads on this topic and I've tried a few things out but nothing seems to be working. My idle never falls below 1000 and most often it sits at 1100-1200. After accelerating I let of the gas and sometimes the idle will drop to 1000 but then find it's way back up and then it will drop back to 1000 and then go back up to 1200 or so and then it will situate itself back at around 1100. It's like it's trying to find a good idle and sometimes it does and it'll stop.
Also, I am hearing what seems to be a vaccum leak, it's a really loud hissing sound coming from around the stock fpr vaccum source but it doesn't seem to be leaking from that.

Things I've tried so far is taking off the iacv (which is on the front of the intake manifold inbetween the intake manifold and valve cover) I took that apart and cleaned it, there was a ---- load of stuff on that little filter. I also tried resetting the ecu, I tried lowering that little screw underneath the throttle rotor so it would idle lower, I tried tightening and loosening the throttle cable but none of this seems to be working.

I'm fine under boost and there is no hesitation or anything, just torque but at idle, whenever it feels like it, it'll start bouncing. Never stalls but that hissing sound is starting to scare me. Anyway, I couldn't find anything else that could help me in past threads but maybe I'm missing something. Oh yah, one final thing, my a/f autometer gauge is acting all wonky, it suddenly is always at red and when I floor it, sometimes it will read almost all the lights on at once, but most of the time it looks dead. After I noticed this, my check engine light came on and then I shut the car off and it hasn't come back on since, but the gauge is still whooped. Any ideas.

Re:bouncing idle
 

check all your vacuum lines. every single one.

Re:bouncing idle
 

which vaccum line usually affects the idle bouncing up and down? Also, which vaccum line is least affected by boost cuz I can hit my full 8-9 psi of boost.

Re:bouncing idle
 

all of them

Re:bouncing idle
 

How erratic is the idle? When I put my new intake manifold on, I had a loose vacuum line that took me hours to find. Either way, it has got to be a loose vacuum line.

Re:bouncing idle
 

It sounds like you blew a vacume line loose under boost, or cracked a plastic valve or fitting. check all of your lines with carb spray, when you hit the leak the idle will go crazy. this explanes your AFM acting up, your motor is geting air your ECM does not know about, you are running lean!

Re:bouncing idle
 

Okay, well after an hour or so of taking ---- apart and cleaning and checking the o rings and stiff like my fast idle valve and iacv and what not, I've finally found the source of my idle bouncing problem. As I was looking for where the hissing was coming from, it was in fact a huge leak that was underneath my fmu. I couldn't see it but after feeling around and ----, I was able to see it. The fmu was butting up against the nipple which caused the nipple to pierce the vaccum line!!

As well, the coolant was a little low so I topped that off, and my engine bay (mostly my intake manifold and throttle body was really dirty because of a crack in my old manifold, I cleaned all that out really well too.

In the end, my idle now sits at around 800 or so (it's hard to tell on my tach, but it's under 1000) and no more bouncing idle. I took it for a rip and I'm still boosting 8-9 psi strong and it feels good. I lift up the hood and there's no more hissing!! Quiet...so quiet and no bouncing!!!! haha. Anyway, hopefully this helps some people out.

Oh yah, and with regards to my air fuel gauge not working properly, the a/f wire that goes to the oxygen sensor reading had disconnected and was grounding itself. I reconnected it and good as new!! No more problems!! Man today is great, all my problems for my car seem to be solved...Knock on wood! Thanks for all the info guys!!