Very very very rich idle

[SoundEfx]

Hey boosted KA peeps.

Before anything is said, I have searched the site concerning my issue and there are a few that came fairly close, but no cigar.

This is my issue.

When I start the car, it will not idle without me giving it some throttle while cranking. Meaning, I give it a constant 2% throttle while cranking and it starts immediate on the second crank. Then after 3 seconds, I could take my foot off the gas and it idles perfectly at 850 rpms and 14.6 - 14.9 afr.

Here is where the fun begins. After 20 - 35 seconds of the perfect idle, the afr's gradually drop to 10.4 or lower and gas is literally being spat out of the exhaust. Watching it drop from 14.7, to 14, then 13.3, then 12.1, to 11.5 and finally to 10's is just like watching money burn right in front of me....lol

Here is the list of the car's specs:
Fuel Pump: Walbro 255
Turbo: Garrett T28 s14 turbo 62 trim A journal bearing t28 off a blacktop jdm S14
MAF: N62 300z maf
Injectors: 370cc injectors
SAFC: Safc2 black
Wideband: Plx m300 wideband. New wideband sensor on that btw. 2mo old
All of that info was presented by the previous owner.

I changed the coolant temp sensors and the o2 sensor and all that did was change the fact that when I drive for approximately 15 - 20 miles, the car occasionally would idle at 11 - 12 afr and that is the part that throws me off. If it was tuned to idle at 10.2, then that shouldn't change when the car is warmed up or happen at random times.

Can anyone help me out because right now I burn less gas in boost than at idle.....lol?

[SoundEfx]

I can't edit my original post, so I'll add this update here.

The car is now getting even harder to start and I was almost left stranded in a parking lot.

If ANYONE could give me a little guidance as to what might be causing this and a way to fix it, it would be greatly appreciated.

[Quantum-Kid]

My S14 SR had almost the same issue. I know this may be stupid to ask but have you checked your spark plugs, spark plug wires, and distributor? I didnt have to give my car throttle upon start up but once my car was on I was running normal a/f ratios then it would steadily run rich to about 10-10.5. Popped my coilpacks and discovered two fried spark plugs. I've never owned a turbo KA but I have had several SR's and a few RB's, why would they tune the car to idle at 10.2 a/f ratios? Stoich (neutral) a/f for an SR is ideally 14, not 10.2 so youre running rich off the bat... Thats just my .02 cents.

[SoundEfx]

Hey Quantum, thanks for trying to help.
I haven't looked at the plugs yet, but I'm in the process of resetting the ecu to see if that makes any difference.
If it doesn't, I'll try changing the plugs, but I know that they'll look terrible.

Also, after changing the coolant sensors, the afr at idle now comes down to 12 rather than 10 as before, so no more stalling when trying to drive away and it's a sign that I'm close or atleast heading in the right direction.