Completely Lean at Any Boost

[Joshky9]

A few weeks back my car died on the highway. I had just got on it a little bit, and there was a complete loss of power. Flat bedded it home and started to try and figure it out. The car would not start at all. The first real breakthrough was the car would start with the MAF unplugged. So we though maybe my GM maf cable went bad. I sent it in and it turned out to be fine. Then we reset MAF comp in dsmlink and now the car starts. Retuned everything at idle and cruise and everything seems good there.

Now for the current problem:
When my car starts building boost (above 0 psi) the wideband goes completely lean. The car bogs loses power and shutters.

What could have caused the original tune to not work all of a sudden?

What could be causing my current problem?

Things we've done:
Replaced the fuel pump and filter
Sealed the FPR adjustment screw
Tried a different GM maf
Boost leak test

Thanks for any input.

Mods 90 talon tsi : EVO II big 16g, walbro 255, 650 cc injectors, dsmlink v3, gm 3 inch maf, aeromotive FPR, wideband o2 sensor

 

[g4ebguy90]

Sounds like a ECU or problem with the link. I don't really know what the link is, but it sounds like a computer problem, rather than a mechanical or sensor problem.

The weird thing is, if it would have a lean misfire, you would think it would turn rich from the unburnt fuel to though.

 

[nightmares GS-T]

Have you checked the o2 sensor voltage to see what its reading under boost?