Checking the fuel pressure is a good idea. I guess it's time to go back to the simple stuff. At peak/upper pressure, you could be losing fuel at an o-ring. You would probably smell it though. I'd replace the FPR/Fuel Inlet/Injector upper o-rings with a set of fatter vitons. You can probably piece them all together from the autoparts stores and have a crap ton left over from all the multi packs.

A few of your early replies stated to swap out the fuel pump. At your power level, I think you might be at the lower-upper limits of the walbro. You still should block tune the MAF comp table and see if higher IDC's get your AFR's striaght. The you can go back to fixing the mechanical issue.

Have you checked your injector resistor pack and also. It's good to get a control of all the related fuel components.

I hope you get this sorted out soon man. Seems like your on the right track.

EDIT:
Aft MAF/Pre Turbo intake leak? Coupler/Perrin Silicone tube/Compressor Housing? I guess a boost leak test may be in order too/unless you did one that I read over.

 

You can try lowering your base static fuel pressure to 35psi and rescale the injectors so fuel trims are within spec. Then retune your WOT and see if that helps? That will get more flow out of your pump.

 

I am having the same issue, problem 2 that is. I have a sc6152re and this inly happens when im on my alternate maps. Its almost like a split second fuel cut/bad mis-fire then accelerates through the powerband just fine. It does not do it on the main map, only alterante.

The only weird thing is that it does in randomly on the secondary maps. Sometimes it will happen sometimes it wont. It seems to happen more regulary when the pull is started from a low rpm, 3k say.

I have checked everything, The car follows the same load pattern and the afr map follows the same pattern. I have tried to lean the car out, richen it up, and add and subtract timing to no effect. It winds up doing it no matter what in the alternate maps. But like I said sometimes it wont do it for me and a lot of times it does.

 

I only have the stock FPR.

I deploy soon so the car will be sitting for a year. I will work on it more upon my return.

Thank you to everyone that has offered to help. I appreciate every one of you for your efforts.

 

After many hours of re-writing my tune into a stock rom and re=flashing the car, I have come to the discovery that my rom was corrupt. Here is the odd thing...After a re-flash I usually hear the relays click. When I was flashing before they were not clicking. So, I tried it again and they clicked. Turn the car off then back on and tried to flash....no click, re-flash without turning off the ignition and they click. Well.... the tune finally took. I believe my mini battery may be the cause of this little issue GRRRR

At any case....the car pulls like mad now. I still get the cutout below 3500 but I am out of time so it will have to wait to be resolved until after I return from the land of sand.

Oh and the car pulled so well that it put down 481hp on the VD......I am stoked ! !

 

I hate corrupt roms man. It can drive you crazy sometimes!

 

I flashed a old rom onto the car then the current rom back on and it fixed my isssue as well. Odd how things can not fully take or get corrupted as you guys are saying.

 

It really seems to happen with the v7 roms more than the standard roms. At least it does in my case.

Just wish I could figure out the cut out issue below 350 rpm.