Weird drivablity issue. Turbo gurus help!

[4g63lover]

So after blowing the diff at the drag strip I decided to just throw another open diff in her. So now, the trans drives good only thing I can pick at is 5th is a little sticky. but other than that its no issue so far.

Though, I am having some driveability issues. I just replaced the intake manifold gasket, throttle body shaft seals, and the throttle body gasket (evo tb gaskets works), and I also deleted the EGR and the evap vacuum switching valves. The car was tuned while taking the leaky shaft seals into consideration.

At idle the AFR's read almost perfect floats around 14.5-15.5 or so. The problem lies during cruise and WOT. AFR's are DAMN rich. It reads 10.0 then it'll go up like its going to hit 14 then drops back to 10.0. It will drive around 13.5 AFR at times but I have yet to experience the AFR's work at its normal 14.3-15.6 fluctuation that it ran on before the drag strip. Also noticed a high pitched noise while driving. Doesnt have to be in boost to occur but I cant duplicate it when the car is in my bay. The rpm's hunt as well when you push the clutch in while driving.

At WOT the car is at 10.0 no matter if I run it @ 15psi or 10psi. I dont think that the EGR delete and the throttle body shaft seals make that much of a difference. She was running around 10.6-11.0 before the diff went. It's gotten hot but I dont think it will cause that much difference. Obviously it runs kinda sluggish being so rich. At times it fills kinda knocky at WOT.

So here's where I am at. It doesnt seem to have a boost leak. i tested it before I took it apart and it was holding fine besides the shaft seals obviously. I have yet to boost leak test it again but I figured after replacing the seals and the gaskets and it still does the same thing its gotta be something else.

I am suspicious of the injectors and the regulator. The perfect idle AFR then wacky cruising WOT AFR's point to the regulator.

I have yet to compression test it but it is safe to say it is not using any coolant and not burning any oil. Atleast not a noticeable amount. And the oil and coolant are clean of each other. So I am taking headgasket problems out of the equation.

I am also suspicious of the MAF. The IAT value was at 132* after a trip around the block but then again my under hood temps get pretty hot.

So that where I am at. I suppose I should pull a plug or two and see their condition.

One last thing, I also put 5 gallons of 100 octane in it and maybe the leaded fuel killed the wideband? I dont know for sure though.

Any help would be appreciated, turbo gurus PLEASE chime in!

[4g63lover]

Thought about it some more today, I wonder if the BOV is leaking causing the high pitched noise?

[Isaurio]

What your fuel trims looks like. Is ur bov rec?

It sounds like a boost leak to me.
If u dont trust wide band check fuel trims it will tell u if u rich on overall afr

[4g63lover]

Long term fuel trims are spot on at 0.0 short term is reading -4.4

yes the bov is recirc but it is the plastic EVO8 BOV

[Isaurio]

Long nevers read on stop and go drive.

Low and mid is where is at.

Yeah u running rich. So did u ever try to tune your injectors?

It most be a boost leak somewhere. Since your low trims is registering rich condition.

[Ivory8g]

First thing that comes to mind is your mag scaling was probably adjusted. Less leaking is probably actually causing the sudden rich conditions. Your car runs on a closes loop at idle so it will target 14.7 automatically and hit it as long as things aren't way off. Open loop is where things change and the car references off the fuel table.

[Silvertune]

Put the EGR back in and throw it in open loop then reset the ECU.

[4g63lover]

The maf scaling wasn't touched ever since the first tune last year. It was acting weird before I did the shaft seals and the EGR delete. It started acting up right after I blew the diff. Matter of fact my first run at the track that day, when I went through the flags and let off the car stalled.