So as many of you have seen I had a very long thread on this and as suggested by another member I'm going to summarize my problem and what i've done to fix it. You can see the main parts that are in my engine build at the bottom of my signature. The car starts up fine on a cold start and fast idles like it should. It will drive fine as I'm going around my block but as I get to the stop sign at the end of my block when I put it in neutral on push the clutch in the rpms will drop and go up and then drop to 0 (Or just drop to 0 without going up and down). When the idle starts to go up and down as I get to this first stop, my lights and stuff will dim and the heater will stop blowing as hard as the rpms drop and then it stalls. However after I get past this one stop sign on my block and the engine is more warmed up, the stalling issue goes away. It does not do this when the engine is warm but sometimes when the engine is shut off and still warm. When I try to start it I need to push the gas pedal a little bit to get it started up.

What I've Done to Fix It:
1) Cleaned IACV, tried 3 different used/cleaned ones with no change in the idle.
2) Replaced the FITV, thermostat, coolant temp sensor (All brand new)
3) Replaced and bled the coolant
3) Checked TPS voltage (.5 closed, 4.6 open)
4) Checked IACV plug for battery voltage (12.8V on one terminal, other side of the plug has no voltage)
5) Removed and cleaned the throttle body as well as the IACV and sprayed carburetor cleaner
6) Adjusted idle screw and throttle cable

The o2 sensor is fairly new as well because I got the new Bosch one with my wideband. I suspect it could be my alternator because starting today I heard a rattling noise around a certain rpm. Sounds like the bearings or bushing might have gone on the alternator and the belt looks like it needs to be tightened a bit.
Any other suggestions are welcomed.

 

Have you replaced your plugs anytime recently? Boosted applications go through plugs much quicker

 

Yep plugs probably only have 2000km on them. I removed the alternator today and was going to get a new one but I had mine tested and its fine. They even took it apart and inspected it and told me the alternator isn't whats making this rattling noise I'm getting. So alternator isnt the problem for the idle eaither, I replaced the belt and put the alternator back on. Any idea what could cause rattling at certain low rpms and also my idle problem?

 

Buy an inexpensive engine stethoscope and then try to pinpoint the source of the rattling noise.

Before you do the next normal driving routine that causes the idle problem, disconnect the O2 sensor to see whether this prevents the problem from occurring.

 

One of my belts is squeaking on startups, I'm not sure if its the alternator belt or the timing belt though. How would I tighten the timing belt?
To try and fix the idle I took my TB off and removed all the gasket maker Iused last time and installed a real gasket. I also cleaned out the throttle body, IACV, and FITV again. It hasn't stalled since it idles really steady on cold and hot starts. I did notice though that when the engine is hot and the car is parked for about 30 minutes sometimes when I start it, it will idle low (~600rpm). Atleast the idle is steady now on cold starts but what could cause a low idle after the car has been sitting with a hot engine? Could it be air in the coolant? To bleed it I just take the cap off the radiator while the car is running and let the bubbles come out and squeeze the hoses, then top it up when the rad fan comes on and the coolant goes down a little. I don't use the bleeder valve on the upperhose because it seems the coolant coming out the hose always looks the same and it seems to add more air every time I top it up with the bleeder valve open. Is there a better way to do it?