I'm posting this for a buddy that doesn't really use forums or even the internet really. Car is a 98 GSX with a built 2.3L 7 bolt. Super 94 turbo on e85 and all supporting mods. It would take all day to list the mods on the car. Car was fully tuned recently and running perfectly. He drove the car out of the garage for some fun one day and the issue just started, nothing had been done since tuning was completed and the car was running perfectly before.

So..... At WOT, when starting at a low RPM and doing a full pull, at around 6500 the car just falls on it face and won't rev past 6500 ish. It's not exactly the same RPM each time but it's close. It doesn't feel like a coil or igniter issue. The first thing I thought was ignition but I rode in the car yesterday and it doesn't miss and feel like when my car was having coil pack issues. If he keeps his foot in it and WOT the car still drives but acts like it's at low throttle. As soon as he lets his foot off the gas and goes part throttle RPMs will rise over 6500. At part throttle the car will rev past 6500 with no issues.

Things that have been tried:
New AEM 5 bar. Manually tested by pumping air into it to 50psi. It is working properly
New CAS
3 different coil packs
1 different igniter
Used with ARC 2 box
Used stock config without ARC 2 box
I'm sure other things have been tried that I've missed.

To reiterate, this car was tuned to 916HP with no issues. The problem just randomly started one day and has not been rememdied at all.

If the car still has a catalytic converter it could be clogged or and possible clogged fuel filter. Running E85 through a standard paper element filter is not recommended so i would start by checking that.

No cats. Bumper exit exhaust. AFR is perfect. No clogged filters.

Do a thorough boost leak check yet?

Yup. BLT done recently

How about new plugs?

According to the posted log, at about 5800 RPMs the MAP sensor reading drops off the face of the earth. Goes from 19psi to idle vacuum. Because of this the AFRs goes from low 12s to high 15s and timing shoots all the way to 38* advanced!

Check the wiring for the AEM MAP sensor asap!

The MAP was manually tested by pumping air into it. It read fine to 50psi. I can't determine if this MAP acting up is a result of some other problem or the cause. This is the second MAP sensor tried and is brand new.[DOUBLEPOST=1417148435][/DOUBLEPOST]Plugs, wires, coil packs, igniter all tried.

New ECU and ECMLink chip tried. No resolution...... Converted to 1g CAS and bypassed crank sensor. No change.

SOUNDED TO ME LIKE FUEL CUT???

BUT IM NO EXPERT.

Nope. No fuel cut.

Problem resolved. He has a front facing turbo and had a rubber hose that went from the compressor cover to the cutout in the headlight for airflow. The turbo was sucking the rubber coupler/hose closed at high boost. Caught it on go pro footage. Car pulls like a freighttrain again.