Idle surging faster then slower

[MR666]

Here is the problem, the car starts up with a slightly fast idle around 1150 rpm and smooth, as it warms up the idle starts to get faster as the fuel air ratio goes down (11:1) and then the fuel air ratio goes really lean around (20.6:1) and then the engine slows down. So the fuel air ratio displayed on the wide band goes up and down with the rpm surge: Here is the back ground: The engine was taken out for major overhaul and everything was touched. Throttle bodies were match bored and no the shafts are not leaking air as I tested for that. The throttle stops were all backed off so the butterfly’s seat on the bores in an attempt to get the idle down. Yes I know this is bad but I am trouble shooting. The Air regulator for idle control is electrically disconnected in an attempt to get the idle down. The AAC idle control for the A/C is electrically disconnected in an attempt to get the idle down. There is now no fuel tank canister and the air bleed for it is blocked at the front throttle body. There are no Narrow band O2 sensors in the pipes but I never had them in before the engine was out and I programmed around their absence. There is a wide band but not hooked into the computer. The MAF’s were working fine before I took the engine out but you never know? I have Nistune and can program it but I have gone through it line by line changing values and getting no fix to the problem. Personally I think it is the fuel air ratio is changing for some reason and I am at a loss as to what it is causing it ?

I do have some Z32 MAF’s but I have to wait for wiring plugs and silicone hoses to arrive to try that idea out. Is there anyone out there who had something similar happen to them cause this is getting to me? . .

It's not the MAF's cause I changed them.

[bobbo]

How does it work off idle?
What is your TPS set at?
Are you sure there is no air in your coolant system?
Try pulling your water temp sensor plug off and see if that makes any difference.
... my first thoughts.

[Skym]

Intake gasket (at throttlebody can cause a high idle) or exhaust gasket leak usually makes the A/F ratio reach as high as 17+. Idle up and down is probably the idle stabilisation tables. If hook up a timing light up you should notice the + and - ignition timing when the rpm rises and falls. Same can be seen in Nistune tuning software with the ECU switching between tables.

The other could be the ECU is detecting knock via knock sensors and is reacting to this.

Usually the up and down idle is related to the o2 sensor detecting the leak.

If MAF's are stuffed the ECU would have a MAF error code and engine idles at around 1500rpm when warm or cold (what happened on my car).

The stock ECU can run without MAF's, so unplugging them and starting engine can eliminate the MAF's as a cause (probably need to clear MAF error code on ECU afterwards).

[MR666]

I removed the air line for the Idle air regulator and plugged it. I think that the air regulator was passing air and even if the ecu called for lower idle it was leaking air. I replaced the stock MAF's back to the Z32's and that made no difference as to which pair I used.
I ended up replacing the ECU with a plug and play Link G4+, I got rid of the MAF's Stock and Z32. The car idles perfectly and I set it by the screw on the throttle cable /crank stop. The car runs good now except my new HKS EVC 6 boost controller isn't working so the car only makes around 530 WHP on no boost. Good enough to break in the engine and then I'll bring on the boost.

Thanks guys for the helping thoughts.